Research ArticleRacialEthnic Nativity and Sociodemographic Disparities inMaternal Hypertension in the United States 2014-2015

Gopal K Singh 1 Mohammad Siahpush 2 Lihua Liu 3 andMichelle Allender1

1Office of Health Equity Health Resources and Services Administration US Department of Health and Human Services5600 Fishers Lane Rockville MD 20857 USA2Department of Health Promotion College of Public Health University of Nebraska Medical Center Omaha NE 68198 USA3Department of Preventive Medicine Keck School of Medicine University of Southern California Los Angeles CA 90032 USA

Correspondence should be addressed to Gopal K Singh gsinghhrsagov

Received 30 November 2017 Revised 13 February 2018 Accepted 17 April 2018 Published 17 May 2018

Academic Editor Franco Veglio

Copyright copy 2018 Gopal K Singh et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This study examines racialethnic nativity and sociodemographic variations in the prevalence of maternal hypertension in theUnited States The 2014-2015 national birth cohort data (119873 = 7966573) were modeled by logistic regression to derive unadjustedand adjusted differentials in maternal hypertension consisting of both pregnancy-related hypertension and chronic hypertensionSubstantial racialethnic differences existed with prevalence of maternal hypertension ranging from 22 for Chinese and 29for Vietnamese women to 89 for American IndiansAlaska Natives (AIANs) and 98 for non-Hispanic blacks Compared withChinese women women in all other ethnic groups had significantly higher risks of maternal hypertension with Filipinos non-Hispanic blacks and AIANs showing 20 to 29 times higher adjusted odds Immigrant women in most racialethnic groups hadlower rates ofmaternal hypertension than theUS-born with prevalence ranging from 19 for Chinese immigrants to 103 forUS-born blacks Increasing maternal age lower education US-born status nonmetropolitan residence prepregnancy obesity excessweight gain during pregnancy and gestational diabetes were other important risk factors AIANs non-Hispanic whites blacksPuerto Ricans and some AsianPacific Islander subgroups were at substantially higher risk of maternal hypertension Ethnicitynativity status older maternal age and prepregnancy obesity and excess weight gain should be included among the criteria usedfor screening for gestational hypertension

1 Introduction

Hypertension in pregnancy is associated with an increasedrisk for a number of pregnancy complications and adversebirth outcomes [1ndash3] Pregnancy-related hypertension is oneof the leading causes of maternal mortality in the UnitedStates [4] Indeed pregnancy-related hypertension alongwith abortion and hemorrhage accounts for approximately50 of all maternal deaths worldwide [5] Women withhypertension in pregnancy have a greater risk of developinghypertension stroke cardiovascular disease and type 2 dia-betes later in life than those without gestational hypertension[1 6ndash8] Women with gestational hypertension also havea significantly higher risk of dysfunctional and prolongedlabor induced labor placental abruption cesarean sectionpostpartum depressive symptoms and poor health status

[1 6ndash8] Gestational hypertension and preeclampsia are alsoimportant risk factors for neonatal morbidity and mortality[1 6ndash8] Preeclampsia is associated with an increased risk ofpreterm birth small for gestational age and low birthweight[1 6ndash8] Children born to hypertensive mothers have beenshown to have higher rates of admission to neonatal intensivecare units resulting in higher healthcare costs [7 8] Childrenof mothers with gestational hypertension are themselves atincreased risk of elevated blood pressure during adolescence[7]

Data from the National Vital Statistics System indicate asteady rise in the prevalence of pregnancy-related hyperten-sion in the United States from 29 in 1989 to 56 in 2015[9] Prevalence of maternal hypertension consisting of bothchronic and pregnancy-related hypertension is more thandoubled from 35 in 1989 to 72 in 2015 [9]

HindawiInternational Journal of HypertensionVolume 2018 Article ID 7897189 14 pageshttpsdoiorg10115520187897189

2 International Journal of Hypertension

In spite of many known adverse health effects ofhypertension in pregnancy racialethnic sociodemographicand medical risk factors associated with increased risk ofmaternal hypertension have not been well studied in theUnited States Although several studies have documentedbroad racialethnic variations in maternal hypertension fewstudies have analyzed variations across a wide range ofracialethnic and immigrant groups in the US [6 8 10ndash13] Specifically the prevalence of maternal hypertension forspecific AsianPacific Islander (API) andHispanic subgroupsis not known In addition although such characteristics asmaternal age smoking marital status maternal educationgestational diabetes prepregnancy body mass index (BMI)and weight gain during pregnancy have been mentioned aspossible risk factors for maternal hypertension few studieshave examined the role of these factors simultaneously [712 13] A better understanding of maternal hypertensionrisks and their determinants among major racialethnic andimmigrant groups is vital to improve maternal health andhealth outcomes among mothers and children in the US

The primary aim of this study was to examine theextent of racialethnic variation in the prevalence of maternalhypertension in the United States and to identify relevantsociodemographic and medical risk factors using nationaldata The study also examines whether racialethnic vari-ation in maternal hypertension varies according to nativ-ityimmigrant status Since immigration is a major charac-teristic of the Asian and Hispanic populations and nearly aquarter of all US births occur among foreign-born mothers[9 14] our analysis is stratified by nativity status to highlightimmigrant differences in maternal hypertension within eachracialethnic group

Maternal hypertension a checkbox item as a medical riskfactor on the birth certificate is defined as blood pressureexceeding 14090mmHg during pregnancy [15] Maternalhypertension includes both chronic (preexisting) hyperten-sion as well as gestational or pregnancy-related hypertension[10 15] We also consider disparities in chronic hypertensionpregnancy-related hypertension and eclampsia separatelyalthough distinguishing different types of hypertensive dis-orders remains a challenge on the birth certificates [15]Eclampsia a serious medical condition is the final stage ofpreeclampsia that causes seizuresconvulsions usually late inthe pregnancy [16]

2 Methods

Thematernal hypertension data in this study are derived fromthe birth certificates filed in the 50 US states the District ofColumbia and New York City [9 15] These data included inthe annual national natality files have been collected on thebirth certificates since 1989 by theCenters forDiseaseControland Preventionrsquos National Center for Health Statistics [9 15]The birth certificate data include awide range ofmaternal andinfant characteristics medical risk factors and complicationsand birth outcomes such as maternal and paternal ageraceethnicity nativity marital status education place ofresidence parity birthweight gestational age prenatal care

tobacco and alcohol use during pregnancy prepregnancyBMI gestational weight gain prepregnancy diabetes gesta-tional diabetes hypertensive disorders in pregnancy uterinebleeding placenta previa prolonged labor and inductionof labor Information on demographic characteristics suchas raceethnicity age nativity marital status educationprepregnancy weight and height and smoking before andduring pregnancy is reported directly by the mother How-ever information on obstetric procedures characteristicsof labor and delivery and medical risk factors such asgestational diabetes and hypertension (chronic gestationaland eclampsia) is collected directly from the medical recordsat the hospital or the freestanding birthing center where thebirth occurs [15 17ndash19] It has to be a confirmed diagnosisof elevated blood pressure for it to be included in thepatientrsquosmedical recordschartsObstetriciansgynecologistsphysician assistants or nurse practitioners are generallythe healthcare providers who make the medical risk factordiagnoses during pregnancy [17 19] Detailed descriptionsof the birth certificate data and national natality files areavailable elsewhere [9 15]

We used the 2014 and 2015 national birth cohort data [915] During 2014-2015 7966573 births occurred among USmothers For all births information on whether or not moth-ers had pregnancy-related or chronic hypertension was avail-able [15] Of 7966573 women who gave birth during 2014-2015 424704 had pregnancy-related hypertension 128267had chronic hypertension and 19278mothers had eclampsiaIn all 552971 mothers were diagnosed with hypertension inpregnancy during 2014-2015 Aggregating data for two yearsensured sufficient sample sizes for analyzing hypertensionpatterns among groups stratified by raceethnicity and immi-grant status

Raceethnicity was classified into 17 major categoriesNon-HispanicwhitesNon-Hispanic blacks AIANsChineseAsian Indians Filipinos Japanese Koreans VietnameseHawaiians Samoans and other AsianPacific Islanders Mex-icans Puerto Ricans Cubans Central and South Americansand other Hispanics Immigrant status was defined on thebasis of mothersrsquo place of birth [9 11 15] US-born categorieswere those born in one of the 50 states or Washington DCImmigrants or foreign-born categories refer to those bornoutside these geographic areas [9 11 15] The joint variableof ethnic-immigrant status included 31 categories with eachracialethnic group divided into the US-born and foreign-born categories Note that although AIANs Hawaiians andSamoans are considered native-born in the present analysisa small percentage of AIANs and Hawaiians and 30 ofSamoans are born outside the 50 states and Washington DC[9 11]

In addition to raceethnicity and immigrant status weconsidered the following sociodemographic andmedical riskfactors associatedwithmaternal hypertension thatwere avail-able in the natality files maternal agemarital statusmaternaleducation metropolitannonmetropolitan residence geo-graphic region of residence gestational diabetes prepreg-nancy BMI gestational weight gain and smoking beforeand during pregnancy [6ndash8 12 13] All covariates exceptsmoking were measured as shown in Tables 1 and 2 Smoking

International Journal of Hypertension 3

Table1Observedprevalence

andmultiv

ariate

logisticregressio

nsshow

ingage-

andcovaria

te-adjusteddifferentialsin

materna

lhypertensionam

ongmajor

racialethnicgrou

psandby

selected

socialandmedicalcharacteris

ticsUnitedStates2014-2015

(119873=79

66573)

Covariate

Num

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SERa

ceethnicity

Non

-Hisp

anicWhite

4322169

717

332lowast

386

371

402

192

184

200

705

001

Non

-Hisp

anicBlack

1188014

982

455lowast

566

544

589

242

232

252

862

003

American

IndianA

laskaN

ative

75204

893

413lowast

519

495

544

200

191

210

732

009

Chinese

116439

216

100

100

Reference

100

Reference

392

008

Japanese

1417

7345

160lowast

149

135

164

150

136

166

566

024

Filip

ino

6316

0774

358lowast

383

365

403

294

279

308

1018

013

Haw

aiian

1725

696

322lowast

380

314

459

158

130

191

592

051

AsianIndian

1315

94398

184lowast

200

190

210

155

148

163

585

008

Korean

3039

0360

167lowast

165

154

177

152

142

164

575

016

Vietnamese

41211

293

136lowast

138

129

148

128

119

137

490

013

Samoan

4316

860

398lowast

489

437

548

162

144

181

605

030

Other

AsianPacific

Island

er140061

445

206lowast

228

217

239

155

147

162

582

007

Mexican

109214

6516

239lowast

279

268

291

148

142

154

560

003

Puerto

Rican

140866

635

294lowast

355

339

371

170

162

178

634

006

Cuban

41270

586

271lowast

310

293

329

182

172

193

673

013

CentralampSouthAmerican

278905

454

210lowast

233

223

243

161

154

168

603

005

Other

Hisp

anic

284926

600

278lowast

332

318

347

169

161

176

629

005

Materna

lage

(years)

lt20484062

630

100

100

Reference

100

Reference

625

004

20ndash24

1733076

609

097lowast

097

095

098

082

081

083

543

002

25ndash29

22977

03648

103lowast

103

102

104

088

086

089

595

002

30ndash34

2175751

699

111lowast

112

110

113

099

097

100

653

002

35ndash39

103674

4850

135lowast

138

136

140

121

119

123

781

003

40ndash4

42218

691134

180lowast

190

187

194

167

164

170

1002

006

ge4517368

1609

255lowast

286

274

298

249

238

261

1400

027

Marita

lstatus

Marrie

d4760176

667

100

100

Reference

100

Reference

620

001

Unm

arrie

d3206397

734

110lowast

125

124

126

107

107

108

655

002

4 International Journal of Hypertension

Table1Con

tinued

Covariate

Num

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SENa

tivity

immigrant

status

USbo

rn6176861

761

165lowast

184

183

186

129

128

130

663

001

Foreignbo

rn17

71387

460

100

100

Reference

100

Reference

510

002

Materna

ledu

catio

n(years)

lt121134548

594

091lowast

102

101

103

092

091

093

659

003

1219

25949

703

108lowast

125

124

126

098

097

099

708

002

13ndash15

22570

33809

124lowast

141

140

142

106

106

107

761

002

ge162343837

650

100

100

Reference

100

Reference

713

002

Plurality

Sing

le76

89433

670

100

100

Reference

100

Reference

616

001

Multip

le277140

1373

205lowast

212

209

214

182

180

184

1066

006

Gestatio

naldiabetes

No

7446

975

626

100

100

Reference

100

Reference

569

001

Yes

508788

1709

287lowast

295

293

297

244

242

246

1324

005

Pre-pregnancyB

MI

Normatweight(BM

Ilt25)

36796

45395

100

100

Reference

100

Reference

354

001

Overw

eight(25leB

MIlt

30)

1923934

686

174lowast

178

177

180

174

173

176

583

002

Obesitygrade1

(30leB

MIlt

35)

1034214

1026

260lowast

277

275

280

269

267

271

845

003

Obesitygrade2

(BMIge

35)

846413

1674

424lowast

491

487

495

460

456

464

1122

005

Weig

htgain

durin

gpregnancy

(lbs)

lt161166852

796

100

100

Reference

100

Reference

541

002

16ndash30

2938813

588

074lowast

110

109

110

112

111

113

577

001

31ndash4

018

99825

605

076lowast

132

130

133

132

131

134

657

002

gt4016

24798

916

115lowast

204

202

206

194

192

195

925

002

Placeo

fresidence

Metropo

litan

coun

ty6353967

668

100

100

Reference

100

Reference

627

001

Non

-metropo

litan

coun

ty16

12606

798

119lowast

127

126

128

104

104

105

657

002

Region

ofresid

ence

New

England

2993

20612

115lowast

115

113

117

110

108

111

555

004

Mid

Atlantic

965794

625

118lowast

119

118

120

110

109

111

524

002

EastNorthcentral

1125412

796

150lowast

160

158

162

124

123

126

669

002

WestN

orthcentral

548470

752

142lowast

151

149

153

119

117

121

636

003

SouthAtlantic

1499665

716

135lowast

142

140

143

115

114

116

640

002

EastSouthcentral

4716

37887

167lowast

185

183

188

135

133

137

777

004

WestS

outhcentral

1116431

751

142lowast

152

151

154

133

132

135

730

003

Mou

ntain

616787

653

123lowast

129

128

131

119

117

120

649

003

Pacific

1323057

530

100

100

Reference

100

Reference

550

002

OR=od

dsratio

CI=

confi

denceintervallowastStatisticallysig

nificantat119901lt0051Definedas

ther

atio

ofthep

revalencefor

aspecificg

roup

tothatforthe

referenceg

roup

2Ad

juste

dform

aternalage

onlyw

eight

gain

odds

werea

djustedform

aternalage

andprepregn

ancy

BMI3Ad

juste

dform

aternalagem

arita

lstatusnativ

itypluralitymaternaledu

catio

nplacea

ndregion

ofresid

encegestatio

naldiabetesprepregn

ancy

BMIandgestationalw

eightg

ain

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafiles

International Journal of Hypertension 5

Table2Observedprevalence

andadjuste

dod

dsof

materna

lhypertensionam

ong32

ethn

ic-im

migrant

grou

psU

nitedStates2014-2015

(119873=79

66573)

Ethn

ic-im

migrant

grou

pNum

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SENon

-Hisp

anicWhiteU

S-bo

rn40319

03739

397lowast

473

452

495

277

265

290

741

001

Non

-Hisp

anicWhiteimmigrant

282556

408

219lowast

232

221

243

173

165

182

485

004

Non

-Hisp

anicBlackUS-bo

rn10

04997

1030

554lowast

727

694

761

347

331

364

901

003

Non

-Hisp

anicBlackim

migrant

1772

9970

8381lowast

413

393

434

263

250

276

707

006

American

IndianA

laskaN

ative

75204

893

480lowast

619

587

652

286

271

301

761

009

ChineseUS-bo

rn14497

425

228lowast

231

210

253

212

193

233

583

022

Chineseim

migrant

1017

5318

610

010

0Re

ference

100

Reference

293

006

JapaneseU

S-bo

rn3893

645

347lowast

343

300

393

302

263

346

798

046

Japaneseimmigrant

10270

232

125lowast

112

098

128

128

111

146

368

023

Haw

aiian

1725

696

374lowast

449

371

543

223

184

271

611

053

Filip

inoUS-bo

rn17216

799

430lowast

483

449

518

343

319

369

891

022

Filip

inoim

migrant

45845

763

410lowast

433

409

458

353

333

373

913

014

AsianIndianU

S-bo

rn1332

3452

243lowast

257

234

282

196

179

216

545

021

AsianIndianimmigrant

118026

391

210lowast

231

218

243

175

165

184

490

007

KoreanU

S-bo

rn6296

381

205lowast

211

184

242

189

165

217

526

032

Koreanimmigrant

2331

3355

191lowast

187

172

203

178

164

194

500

016

VietnameseUS-bo

rn77

13455

245lowast

279

248

313

222

197

249

607

030

Vietnameseim

migrant

33453

256

138lowast

137

126

148

132

122

143

379

012

Samoan

4316

860

462lowast

581

517

652

214

190

241

589

030

Other

AsianPacific

Island

erU

S-bo

rn51424

511

275lowast

323

305

343

209

197

222

577

011

Other

AsianPacific

Island

erimmigrant

87782

405

217lowast

237

224

250

178

168

188

498

008

MexicanU

S-bo

rn554774

579

312lowast

395

376

413

206

196

216

569

003

Mexicanimmigrant

536471

451

243lowast

272

260

285

170

162

179

479

003

Puerto

Rican

mainlandUS-bo

rn1215

54626

336lowast

416

396

438

234

222

246

637

007

Puerto

Rican

Puerto

Rico-born

1853

070

4379lowast

458

426

492

255

237

274

688

018

Cuban

US-bo

rn19864

616

331lowast

391

363

420

229

213

247

626

017

Cuban

immigrant

21389

559

300lowast

343

319

370

234

217

252

637

017

CentralampSouthAmericanU

S-bo

rn47914

530

285lowast

347

327

369

208

195

221

573

011

CentralampSouthAmericanimmigrant

230721

439

236lowast

260

247

273

184

175

194

514

005

Other

Hisp

anicU

S-bo

rn202960

604

325lowast

410

391

431

221

210

232

606

005

Other

Hisp

anicimmigrant

81468

590

317lowast

361

342

381

241

228

254

654

009

Allothere

thnic-nativ

itygrou

ps1812

4691

371lowast

438

407

471

287

266

309

764

020

OR=od

dsratio

CI=

confi

denceintervallowastStatisticallysig

nificantat119901lt0051Definedas

ther

atioof

thep

revalencefor

aspecific

grou

pto

thatforthe

referenceg

roup

2Ad

juste

dform

aternalage

only3Ad

juste

dform

aternalagem

arita

lstatuspluralitym

aternaledu

catio

nplacea

ndregion

ofresid

encegestatio

naldiabetesprepregn

ancy

BMIandgestationalw

eightgainSourceD

atad

erived

fromthe2

014-2015USN

ational

Natality

datafiles

6 International Journal of Hypertension

before and during pregnancy was defined as dichotomousvariables with ldquoyesrdquo and ldquonordquo categories

Prevalence estimates and prevalence ratios were usedto describe the overall association between covariates andmaternal hypertension Prevalence ratio was defined as theratio of the prevalence for a specific group to that for thereference group Multivariable logistic regression was usedto model the adjusted association between each sociodemo-graphic characteristic and the risk of maternal hypertensionpregnancy-related hypertension chronic hypertension oreclampsia [20] In estimating the odds of hypertension forraceethnicity and ethnic-immigrant status we consideredChinese women or Chinese immigrant women as the refer-ence group based on prior research and because they had thelowest prevalence which could potentially be achievable byother population subgroups [11 21 22] Fitted logistic modelswere used to derive adjusted hypertension prevalence atmeanvalues of the covariates [20 21]

An index of disparity which approximated in relativeterms the average deviation of the rates from the rate for thebest-off racialethnic or ethnic-nativity group was used tosummarize hypertension disparities across all groups [23 24]This relativemean deviation index of disparity was calculatedas

ID = (sum119894 1003816100381610038161003816119867119903119894 minus 1198671199031198971003816100381610038161003816 119868)119867119903119897 times 100 119867119903119897 gt 0 (1)

where 119867119903119894 is the hypertension prevalence for the 119894th group(119894 = 1 2 3 31) 119867119903119897 is the prevalence for the group withthe lowest prevalence (ie Chinese women) and 119868 is thenumber of racialethnic (17) or ethnic-immigrant groups (31)being compared [20]

3 Results

During 2014-2015 the overall prevalence of maternal hyper-tension in the US was 69 About 53 of women hadpregnancy-related hypertension and 16 had chronic hyper-tension Substantial racialethnic differences existed in theprevalence of maternal hypertension ranging from 22for Chinese and 29 for Vietnamese women to 89 forAmerican IndiansAlaska Natives (AIANs) and 98 fornon-Hispanic blacks (Table 1) Compared to non-Hispanicwhite women other Asian groups such as Japanese Kore-ans and Asian Indians had significantly lower prevalencewhile Filipinos Samoans AIANs and non-Hispanic blackshad significantly higher prevalence Compared to Chinesewomen women in all other racialethnic groups had signif-icantly higher risks of maternal hypertension Among APIwomen Samoans Filipinos and Hawaiians had the highestprevalence of maternal hypertension Among HispanicsPuerto Ricans had the highest prevalence (64) followedby Cubans Mexicans and Central and South AmericansHowever the prevalence for all Hispanic subgroups wassignificantly lower than the prevalence of 72 for non-Hispanic whites (Table 1)

Immigrant women in most racialethnic groups hadlower rates of maternal hypertension than their US-born

counterparts with the prevalence ranging from 19 forChinese immigrants and 23 for Japanese immigrants to103 for US-born blacks (Table 2) For example Chineseimmigrants had a 56 lower risk of maternal hypertensionthan US-born Chinese Vietnamese immigrants had a 44lower risk thanUS-born Vietnamese black immigrants had a31 lower risk thanUS-born blacksMexican immigrants hada 22 lower risk than US-born Mexicans and non-Hispanicwhite immigrants had a 45 lower risk than US-born non-Hispanic whites

Racialethnic groups varied greatly in their sociodemo-graphic and medical characteristics known to be associatedwith maternal hypertension (Table 3) For example whilelt13 of births occurred among AIAN Puerto Rican andblackmothers agedge35 years this percentagewas 32amongChinese and Filipinos 37 among Koreans and 49 amongJapanese mothers Educational attainment was the highestamong Asian Indian and Korean women and the lowestamong Mexican and Samoan women The percentage ofmothers with a college degree ranged from 767 for Koreansand 783 for Asian Indians to 74 for Samoans 91 forMexicans and 92 for AIANs More than 87 of Chineseand Asian Indian mothers were foreign-born comparedwith 66 of non-Hispanic whites and 150 of blacksThe prevalence of gestational diabetes was 133 for AsianIndians 119 for Filipinos 116 for Vietnamese 101 forSamoans 10 for AIANs and 95 for Chinese comparedwith 56 for blacks and 57 for non-Hispanic whitesSamoan women had the highest prevalence of prepregnancyobesity (644) followed by Hawaiians (372) AIANs(360) blacks (350) Puerto Ricans (299) and Mexi-cans (291) Chinese women had the lowest prepregnancyobesity prevalence (27) Samoans Hawaiians CubansPuerto Ricans non-Hispanic Whites Blacks and AIANswere significantly more likely to experience excess weightgain (gt40 pounds) during pregnancy compared to womenin all Asian subgroups Approximately 223 of AIANsand 149 of non-Hispanic whites reported having smokedbefore pregnancy compared with lt3 of Asian mothersRacialethnic patterns in smoking during pregnancy weresimilar

After controlling for covariates women in allracialethnic groups had significantly higher risks ofmaternalhypertension compared to Chinese women (Table 1 Model2) Compared with Chinese women non-Hispanic whitesAIANs non-Hispanic blacks and Filipinos had respectively19 20 24 and 29 times higher adjusted odds of maternalhypertension Compared with Chinese women MexicansCentral and South Americans Puerto Ricans and Cubanshad respectively 15 16 17 and 18 times higher adjustedodds of maternal hypertension Compared with Chineseimmigrants the adjusted odds of maternal hypertensionwere 21 times higher for US-born Chinese 26 times higherfor black immigrants 35 times higher for US-born blacks17 times higher for non-Hispanic whites 28 times higher forUS-born non-Hispanic whites 35 times higher for Filipinoimmigrants 34 times higher for US-born Filipinos 30times higher for US-born Japanese and 29 times higher forAIANs (Table 2 Model 2) Sociodemographic and medical

International Journal of Hypertension 7

Table3Ra

cialethnicv

ariatio

nin

selected

socialandmedicalris

kfactorsfor

materna

lhypertensionUnitedStates2014-2015

(119873=79

66573)

RaceEthnicity

MaternalA

gege

35Years

Percent

Maternal

Educationge16

Years

Percent

ForeignBo

rnPercent

Gestatio

nal

Diabetes

Percent

Pre-pregnancy

Overw

eight(BM

Ige2

5)Prevalence

()

Pre-pregnancy

Obesity(BMIge

30)

Prevalence

()

Weightg

ainin

pregnancy

(gt40lbs)

Prevalence

()

Smok

ingBe

fore

Pregnancy

Percent

Smok

ingin

Pregnancy

Percent

AllRa

ces

160

306

223

64

508

251

213

105

81

Non

-Hisp

anicWhite

163

396

66

57

473

231

240

149

116

Non

-Hisp

anicBlack

128

159

150

56

618

350

217

9069

American

IndianA

N100

9216

100

631

360

228

223

179

Chinese

316

675

875

95143

27

147

04

02

Japanese

494

665

725

62

163

48

7721

09

Filip

ino

319

531

727

119

363

117

160

23

12As

ianIndian

187

783

899

133

377

98130

03

02

Korean

365

767

787

79199

50

141

26

14Vietnamese

292

399

813

116

158

36

129

1006

Haw

aiian

145

181

44

83

650

372

248

147

123

Samoan

120

74296

101

876

644

312

9981

Mexican

145

91492

76593

291

155

24

15Pu

erto

Rican

120

154

132

67

568

299

223

101

68

Cuban

170

266

519

52

471

199

257

35

23

CentralSou

thAmerican

208

175

828

64

520

205

149

1206

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafilesA

N=AlaskaN

ative

8 International Journal of Hypertension

risk factors accounted for 63 of racialethnic disparitiesand 46 of ethnic-immigrant disparities in maternalhypertension based on comparison of the disparity indicesfor the unadjusted and adjusted prevalence estimates (datanot shown)

Table 1 shows variation in the prevalence and odds ofmaternal hypertension according to other sociodemographiccharacteristics Increasing maternal age unmarried statusUS-born status lower education nonmetropolitan residenceresidence in the Southern United States prepregnancy obe-sity excess weight gain during pregnancy and gestationaldiabetes were all associated with increased risks of maternalhypertensionWomen aged 40ndash44 andge45 years had respec-tively 17 and 25 times higher adjusted odds of maternalhypertension than those aged lt20 years Women with ges-tational diabetes had a 27 times higher prevalence and 24times higher adjusted odds of maternal hypertension thanthose who did not have gestational diabetes Compared towomen with normal weight (BMI lt 25) overweight womenas well as women with grade 1 and grade 2 obesity hadrespectively 17 27 and 46 times higher adjusted odds ofmaternal hypertension Women who gained gt40 pounds had94 higher adjusted odds of maternal hypertension thanthose who gained lt16 pounds during pregnancy Women inthe Southeastern and SouthwesternUnited States had 33ndash35higher adjusted odds of maternal hypertension than thoseliving in the Pacific region Although smoking during andbefore pregnancy was associated with 10 and 18 higherodds of maternal hypertension respectively after controllingfor sociodemographic and medical risk factors smoking wasfound to be not significantly related tomaternal hypertension(data not shown)

Racialethnic and ethnic-immigrant disparities in preg-nancy-related hypertension and chronic hypertension pre-sented in Tables 4 and 5 respectively generally show patternssimilar to those for the combined outcome ofmaternal hyper-tension However the effect-sizes for some risk factors suchas maternal age prepregnancy BMI smoking during andbefore pregnancy education and geographic residence werestronger for chronic hypertension than for pregnancy-relatedhypertension (data not shown for brevity) For examplecompared to those aged lt20 years women aged 40ndash44 andge45 years had respectively 88 and 120 times higher adjustedodds of chronic hypertension and 11 and 16 times higheradjusted odds of pregnancy-related hypertension Grade 1and grade 2 prepregnancy obesity were associated with 37and 78 times higher adjusted odds of chronic hypertensionand 25 and 37 times higher adjusted odds of pregnancy-related hypertension While maternal education was notsignificantly related to pregnancy-related hypertension aftercontrolling for other covariates there was a consistentand inverse educational gradient in chronic hypertensionWomen with less than a high school education had 30higher adjusted odds of chronic hypertension than those witha college degree Women in the Southeastern United Stateshad 87 higher adjusted odds and those in the New Englandregion had 62higher adjusted odds of chronic hypertensionthan those living in the Pacific region While smoking wasnot significantly related to pregnancy-related hypertension

smoking before and during pregnancy was associated with30ndash33higher risks of chronic hypertension Smoking beforeor during pregnancy was associated with 58-59 higher age-adjusted odds of chronic hypertension and 17-18 highercovariate-adjusted odds of chronic hypertension

Racialethnic variations in eclampsia were similar tothose for chronic andpregnancy-related hypertension Preva-lence of eclampsia was the highest among Samoan HawaiianNon-Hispanic black AIAN and Filipino women and thelowest among Chinese Vietnamese and Korean women(Figure 1) Compared with Chinese women blacks JapaneseSamoans Filipinos and Hawaiians had 3 to 4 times higheradjusted odds of eclampsia (data not shown) Immigrantwomen in most racialethnic groups had a lower risk ofeclampsia than their US-born counterparts The rate ofeclampsia ranged from 06 per 1000 live births for Chineseimmigrant women to 52 for Hawaiians and 53 per 1000 livebirths for Samoans (Figure 1) Chinese immigrants had 47lower adjusted odds than US-born Chinese Japanese immi-grants had 72 lower adjusted odds than US-born Japaneseblack immigrants had 17 lower adjusted odds thanUS-bornblacks and white immigrants had 19 lower adjusted odds ofeclampsia than US-born whites (data not shown) Maternalage lt 20 and ge45 years was associated with substantiallyincreased risks of eclampsia Women in the Southeast regionhad 23 times higher adjusted odds of eclampsia than those inthe Pacific region Gestational diabetes grade 1 prepregnancyobesity and grade 2 prepregnancy obesity were associatedwith 20 20 and 27 times higher adjusted odds of eclampsiarespectively (data not shown)

4 Discussion

To our knowledge this is the largest population-based studyof maternal hypertension in the United States The resultsof this national study indicate substantial racialethnic andnativity differences in the risk of maternal hypertensionwhich were only partially explained by differences in mater-nal age education prepregnancy BMI weight gain duringpregnancy gestational diabetes and other relevant sociode-mographic characteristics The detailed analysis of maternalhypertension prevalence among specific API and Hispanicsubgroups as well as among a large number of immigrantgroups is a particularly novel feature of our study Theincreased risks ofmaternal hypertension amongAIANs non-Hispanic whites blacks and Puerto Ricans are consistentwith those reported in previous US studies [6 8 10ndash12]Significantly higher risks of maternal hypertension amongFilipinos Samoans and Hawaiians and lower risks amongother Asian groups such as Chinese Japanese Koreans andVietnamese reported in our study are consistent with two USstudies conducted in Hawaii and New York City that showsimilar racialethnic patterns in maternal hypertension andpreeclampsia [8 13] Our findings of lower risks of maternalhypertension among Mexicans Cubans and CentralSouthAmericans are compatible with previous studies that showlower risks of hypertension among Hispanics compared tonon-Hispanic whites but higher risks amongHispanics whencompared to Asian groups [4 8 11 12]

International Journal of Hypertension 9

Table 4 Observed prevalence and adjusted odds of pregnancy-related hypertension among 17 racialethnic and 31 ethnic-immigrant groupsUnited States 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 567 322lowast 348 333 364 196 187 205Non-Hispanic Black 655 372lowast 408 390 426 205 196 215American IndianAlaska Native 677 385lowast 425 404 448 196 186 207Chinese 176 100 100 Reference 100 ReferenceJapanese 269 153lowast 147 132 165 150 134 168Filipino 587 334lowast 348 330 368 274 259 289Hawaiian 562 319lowast 346 281 427 167 135 207Asian Indian 326 185lowast 194 184 205 156 148 164Korean 277 157lowast 158 145 171 146 135 159Vietnamese 242 138lowast 138 128 150 131 122 142Samoan 681 387lowast 429 378 486 166 146 189Other AsianPacific Islander 350 199lowast 209 198 220 155 147 163Mexican 428 243lowast 259 248 271 156 149 163Puerto Rican 473 269lowast 290 276 305 167 158 175Cuban 477 271lowast 290 272 308 188 176 200Central amp South American 359 204lowast 213 203 223 164 156 172Other Hispanic 486 276lowast 297 284 311 172 164 180Ethnic-immigrant statusNon-Hispanic White US-born 584 382lowast 420 441 400 263 277 251Non-Hispanic White immigrant 330 216lowast 222 228 216 173 178 168Non-Hispanic Black US-born 683 446lowast 506 526 486 272 283 261Non-Hispanic Black immigrant 491 321lowast 335 344 326 234 241 228American IndianAlaska Native 677 442lowast 500 510 490 260 266 255Chinese US-born 337 220lowast 223 214 233 202 194 211Chinese immigrant 153 100 100 Reference 100 ReferenceJapanese US-born 475 310lowast 311 281 343 269 244 298Japanese immigrant 192 125lowast 118 107 130 133 122 146Hawaiian 562 367lowast 405 346 473 220 188 258Filipino US-born 609 398lowast 428 421 434 308 304 313Filipino immigrant 579 378lowast 393 396 390 324 328 322Asian Indian US-born 374 244lowast 255 244 265 199 191 207Asian Indian immigrant 320 209lowast 221 225 218 173 176 171Korean US-born 291 190lowast 195 176 215 172 156 190Korean immigrant 275 180lowast 179 173 184 170 165 175Vietnamese US-born 377 246lowast 266 248 285 213 199 229Vietnamese immigrant 210 137lowast 137 133 141 136 132 139Samoan 681 445lowast 503 468 539 209 195 224Other AsianPacific Islander US-born 405 265lowast 287 288 286 196 197 195Other AsianPacific Islander immigrant 318 208lowast 217 219 215 178 180 176Mexican US-born 482 315lowast 350 363 338 200 207 193Mexican immigrant 372 243lowast 258 266 249 181 188 175Puerto Rican mainland US-born 469 307lowast 338 345 330 216 220 211Puerto Rican Puerto Rico-born 509 333lowast 363 357 370 228 225 233Cuban US-born 492 322lowast 351 345 357 221 218 225Cuban immigrant 464 303lowast 326 321 331 239 236 243Central amp South American US-born 422 276lowast 302 302 300 195 196 194Central amp South American immigrant 346 226lowast 237 243 231 188 193 183Other Hispanic US-born 499 326lowast 363 373 352 213 220 208Other Hispanic immigrant 455 297lowast 317 322 312 235 239 232All other ethnic-nativity groups 523 342lowast 371 364 377 265 261 270OR = odds ratio CI = confidence interval lowastStatistically significant at 119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that forthe reference group 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region ofresidence gestational diabetes prepregnancy BMI and gestational weight gain Source Data derived from the 2014-2015 US National Natality data files

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

International Journal of Hypertension 3

Table1Observedprevalence

andmultiv

ariate

logisticregressio

nsshow

ingage-

andcovaria

te-adjusteddifferentialsin

materna

lhypertensionam

ongmajor

racialethnicgrou

psandby

selected

socialandmedicalcharacteris

ticsUnitedStates2014-2015

(119873=79

66573)

Covariate

Num

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SERa

ceethnicity

Non

-Hisp

anicWhite

4322169

717

332lowast

386

371

402

192

184

200

705

001

Non

-Hisp

anicBlack

1188014

982

455lowast

566

544

589

242

232

252

862

003

American

IndianA

laskaN

ative

75204

893

413lowast

519

495

544

200

191

210

732

009

Chinese

116439

216

100

100

Reference

100

Reference

392

008

Japanese

1417

7345

160lowast

149

135

164

150

136

166

566

024

Filip

ino

6316

0774

358lowast

383

365

403

294

279

308

1018

013

Haw

aiian

1725

696

322lowast

380

314

459

158

130

191

592

051

AsianIndian

1315

94398

184lowast

200

190

210

155

148

163

585

008

Korean

3039

0360

167lowast

165

154

177

152

142

164

575

016

Vietnamese

41211

293

136lowast

138

129

148

128

119

137

490

013

Samoan

4316

860

398lowast

489

437

548

162

144

181

605

030

Other

AsianPacific

Island

er140061

445

206lowast

228

217

239

155

147

162

582

007

Mexican

109214

6516

239lowast

279

268

291

148

142

154

560

003

Puerto

Rican

140866

635

294lowast

355

339

371

170

162

178

634

006

Cuban

41270

586

271lowast

310

293

329

182

172

193

673

013

CentralampSouthAmerican

278905

454

210lowast

233

223

243

161

154

168

603

005

Other

Hisp

anic

284926

600

278lowast

332

318

347

169

161

176

629

005

Materna

lage

(years)

lt20484062

630

100

100

Reference

100

Reference

625

004

20ndash24

1733076

609

097lowast

097

095

098

082

081

083

543

002

25ndash29

22977

03648

103lowast

103

102

104

088

086

089

595

002

30ndash34

2175751

699

111lowast

112

110

113

099

097

100

653

002

35ndash39

103674

4850

135lowast

138

136

140

121

119

123

781

003

40ndash4

42218

691134

180lowast

190

187

194

167

164

170

1002

006

ge4517368

1609

255lowast

286

274

298

249

238

261

1400

027

Marita

lstatus

Marrie

d4760176

667

100

100

Reference

100

Reference

620

001

Unm

arrie

d3206397

734

110lowast

125

124

126

107

107

108

655

002

4 International Journal of Hypertension

Table1Con

tinued

Covariate

Num

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SENa

tivity

immigrant

status

USbo

rn6176861

761

165lowast

184

183

186

129

128

130

663

001

Foreignbo

rn17

71387

460

100

100

Reference

100

Reference

510

002

Materna

ledu

catio

n(years)

lt121134548

594

091lowast

102

101

103

092

091

093

659

003

1219

25949

703

108lowast

125

124

126

098

097

099

708

002

13ndash15

22570

33809

124lowast

141

140

142

106

106

107

761

002

ge162343837

650

100

100

Reference

100

Reference

713

002

Plurality

Sing

le76

89433

670

100

100

Reference

100

Reference

616

001

Multip

le277140

1373

205lowast

212

209

214

182

180

184

1066

006

Gestatio

naldiabetes

No

7446

975

626

100

100

Reference

100

Reference

569

001

Yes

508788

1709

287lowast

295

293

297

244

242

246

1324

005

Pre-pregnancyB

MI

Normatweight(BM

Ilt25)

36796

45395

100

100

Reference

100

Reference

354

001

Overw

eight(25leB

MIlt

30)

1923934

686

174lowast

178

177

180

174

173

176

583

002

Obesitygrade1

(30leB

MIlt

35)

1034214

1026

260lowast

277

275

280

269

267

271

845

003

Obesitygrade2

(BMIge

35)

846413

1674

424lowast

491

487

495

460

456

464

1122

005

Weig

htgain

durin

gpregnancy

(lbs)

lt161166852

796

100

100

Reference

100

Reference

541

002

16ndash30

2938813

588

074lowast

110

109

110

112

111

113

577

001

31ndash4

018

99825

605

076lowast

132

130

133

132

131

134

657

002

gt4016

24798

916

115lowast

204

202

206

194

192

195

925

002

Placeo

fresidence

Metropo

litan

coun

ty6353967

668

100

100

Reference

100

Reference

627

001

Non

-metropo

litan

coun

ty16

12606

798

119lowast

127

126

128

104

104

105

657

002

Region

ofresid

ence

New

England

2993

20612

115lowast

115

113

117

110

108

111

555

004

Mid

Atlantic

965794

625

118lowast

119

118

120

110

109

111

524

002

EastNorthcentral

1125412

796

150lowast

160

158

162

124

123

126

669

002

WestN

orthcentral

548470

752

142lowast

151

149

153

119

117

121

636

003

SouthAtlantic

1499665

716

135lowast

142

140

143

115

114

116

640

002

EastSouthcentral

4716

37887

167lowast

185

183

188

135

133

137

777

004

WestS

outhcentral

1116431

751

142lowast

152

151

154

133

132

135

730

003

Mou

ntain

616787

653

123lowast

129

128

131

119

117

120

649

003

Pacific

1323057

530

100

100

Reference

100

Reference

550

002

OR=od

dsratio

CI=

confi

denceintervallowastStatisticallysig

nificantat119901lt0051Definedas

ther

atio

ofthep

revalencefor

aspecificg

roup

tothatforthe

referenceg

roup

2Ad

juste

dform

aternalage

onlyw

eight

gain

odds

werea

djustedform

aternalage

andprepregn

ancy

BMI3Ad

juste

dform

aternalagem

arita

lstatusnativ

itypluralitymaternaledu

catio

nplacea

ndregion

ofresid

encegestatio

naldiabetesprepregn

ancy

BMIandgestationalw

eightg

ain

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafiles

International Journal of Hypertension 5

Table2Observedprevalence

andadjuste

dod

dsof

materna

lhypertensionam

ong32

ethn

ic-im

migrant

grou

psU

nitedStates2014-2015

(119873=79

66573)

Ethn

ic-im

migrant

grou

pNum

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SENon

-Hisp

anicWhiteU

S-bo

rn40319

03739

397lowast

473

452

495

277

265

290

741

001

Non

-Hisp

anicWhiteimmigrant

282556

408

219lowast

232

221

243

173

165

182

485

004

Non

-Hisp

anicBlackUS-bo

rn10

04997

1030

554lowast

727

694

761

347

331

364

901

003

Non

-Hisp

anicBlackim

migrant

1772

9970

8381lowast

413

393

434

263

250

276

707

006

American

IndianA

laskaN

ative

75204

893

480lowast

619

587

652

286

271

301

761

009

ChineseUS-bo

rn14497

425

228lowast

231

210

253

212

193

233

583

022

Chineseim

migrant

1017

5318

610

010

0Re

ference

100

Reference

293

006

JapaneseU

S-bo

rn3893

645

347lowast

343

300

393

302

263

346

798

046

Japaneseimmigrant

10270

232

125lowast

112

098

128

128

111

146

368

023

Haw

aiian

1725

696

374lowast

449

371

543

223

184

271

611

053

Filip

inoUS-bo

rn17216

799

430lowast

483

449

518

343

319

369

891

022

Filip

inoim

migrant

45845

763

410lowast

433

409

458

353

333

373

913

014

AsianIndianU

S-bo

rn1332

3452

243lowast

257

234

282

196

179

216

545

021

AsianIndianimmigrant

118026

391

210lowast

231

218

243

175

165

184

490

007

KoreanU

S-bo

rn6296

381

205lowast

211

184

242

189

165

217

526

032

Koreanimmigrant

2331

3355

191lowast

187

172

203

178

164

194

500

016

VietnameseUS-bo

rn77

13455

245lowast

279

248

313

222

197

249

607

030

Vietnameseim

migrant

33453

256

138lowast

137

126

148

132

122

143

379

012

Samoan

4316

860

462lowast

581

517

652

214

190

241

589

030

Other

AsianPacific

Island

erU

S-bo

rn51424

511

275lowast

323

305

343

209

197

222

577

011

Other

AsianPacific

Island

erimmigrant

87782

405

217lowast

237

224

250

178

168

188

498

008

MexicanU

S-bo

rn554774

579

312lowast

395

376

413

206

196

216

569

003

Mexicanimmigrant

536471

451

243lowast

272

260

285

170

162

179

479

003

Puerto

Rican

mainlandUS-bo

rn1215

54626

336lowast

416

396

438

234

222

246

637

007

Puerto

Rican

Puerto

Rico-born

1853

070

4379lowast

458

426

492

255

237

274

688

018

Cuban

US-bo

rn19864

616

331lowast

391

363

420

229

213

247

626

017

Cuban

immigrant

21389

559

300lowast

343

319

370

234

217

252

637

017

CentralampSouthAmericanU

S-bo

rn47914

530

285lowast

347

327

369

208

195

221

573

011

CentralampSouthAmericanimmigrant

230721

439

236lowast

260

247

273

184

175

194

514

005

Other

Hisp

anicU

S-bo

rn202960

604

325lowast

410

391

431

221

210

232

606

005

Other

Hisp

anicimmigrant

81468

590

317lowast

361

342

381

241

228

254

654

009

Allothere

thnic-nativ

itygrou

ps1812

4691

371lowast

438

407

471

287

266

309

764

020

OR=od

dsratio

CI=

confi

denceintervallowastStatisticallysig

nificantat119901lt0051Definedas

ther

atioof

thep

revalencefor

aspecific

grou

pto

thatforthe

referenceg

roup

2Ad

juste

dform

aternalage

only3Ad

juste

dform

aternalagem

arita

lstatuspluralitym

aternaledu

catio

nplacea

ndregion

ofresid

encegestatio

naldiabetesprepregn

ancy

BMIandgestationalw

eightgainSourceD

atad

erived

fromthe2

014-2015USN

ational

Natality

datafiles

6 International Journal of Hypertension

before and during pregnancy was defined as dichotomousvariables with ldquoyesrdquo and ldquonordquo categories

Prevalence estimates and prevalence ratios were usedto describe the overall association between covariates andmaternal hypertension Prevalence ratio was defined as theratio of the prevalence for a specific group to that for thereference group Multivariable logistic regression was usedto model the adjusted association between each sociodemo-graphic characteristic and the risk of maternal hypertensionpregnancy-related hypertension chronic hypertension oreclampsia [20] In estimating the odds of hypertension forraceethnicity and ethnic-immigrant status we consideredChinese women or Chinese immigrant women as the refer-ence group based on prior research and because they had thelowest prevalence which could potentially be achievable byother population subgroups [11 21 22] Fitted logistic modelswere used to derive adjusted hypertension prevalence atmeanvalues of the covariates [20 21]

An index of disparity which approximated in relativeterms the average deviation of the rates from the rate for thebest-off racialethnic or ethnic-nativity group was used tosummarize hypertension disparities across all groups [23 24]This relativemean deviation index of disparity was calculatedas

ID = (sum119894 1003816100381610038161003816119867119903119894 minus 1198671199031198971003816100381610038161003816 119868)119867119903119897 times 100 119867119903119897 gt 0 (1)

where 119867119903119894 is the hypertension prevalence for the 119894th group(119894 = 1 2 3 31) 119867119903119897 is the prevalence for the group withthe lowest prevalence (ie Chinese women) and 119868 is thenumber of racialethnic (17) or ethnic-immigrant groups (31)being compared [20]

3 Results

During 2014-2015 the overall prevalence of maternal hyper-tension in the US was 69 About 53 of women hadpregnancy-related hypertension and 16 had chronic hyper-tension Substantial racialethnic differences existed in theprevalence of maternal hypertension ranging from 22for Chinese and 29 for Vietnamese women to 89 forAmerican IndiansAlaska Natives (AIANs) and 98 fornon-Hispanic blacks (Table 1) Compared to non-Hispanicwhite women other Asian groups such as Japanese Kore-ans and Asian Indians had significantly lower prevalencewhile Filipinos Samoans AIANs and non-Hispanic blackshad significantly higher prevalence Compared to Chinesewomen women in all other racialethnic groups had signif-icantly higher risks of maternal hypertension Among APIwomen Samoans Filipinos and Hawaiians had the highestprevalence of maternal hypertension Among HispanicsPuerto Ricans had the highest prevalence (64) followedby Cubans Mexicans and Central and South AmericansHowever the prevalence for all Hispanic subgroups wassignificantly lower than the prevalence of 72 for non-Hispanic whites (Table 1)

Immigrant women in most racialethnic groups hadlower rates of maternal hypertension than their US-born

counterparts with the prevalence ranging from 19 forChinese immigrants and 23 for Japanese immigrants to103 for US-born blacks (Table 2) For example Chineseimmigrants had a 56 lower risk of maternal hypertensionthan US-born Chinese Vietnamese immigrants had a 44lower risk thanUS-born Vietnamese black immigrants had a31 lower risk thanUS-born blacksMexican immigrants hada 22 lower risk than US-born Mexicans and non-Hispanicwhite immigrants had a 45 lower risk than US-born non-Hispanic whites

Racialethnic groups varied greatly in their sociodemo-graphic and medical characteristics known to be associatedwith maternal hypertension (Table 3) For example whilelt13 of births occurred among AIAN Puerto Rican andblackmothers agedge35 years this percentagewas 32amongChinese and Filipinos 37 among Koreans and 49 amongJapanese mothers Educational attainment was the highestamong Asian Indian and Korean women and the lowestamong Mexican and Samoan women The percentage ofmothers with a college degree ranged from 767 for Koreansand 783 for Asian Indians to 74 for Samoans 91 forMexicans and 92 for AIANs More than 87 of Chineseand Asian Indian mothers were foreign-born comparedwith 66 of non-Hispanic whites and 150 of blacksThe prevalence of gestational diabetes was 133 for AsianIndians 119 for Filipinos 116 for Vietnamese 101 forSamoans 10 for AIANs and 95 for Chinese comparedwith 56 for blacks and 57 for non-Hispanic whitesSamoan women had the highest prevalence of prepregnancyobesity (644) followed by Hawaiians (372) AIANs(360) blacks (350) Puerto Ricans (299) and Mexi-cans (291) Chinese women had the lowest prepregnancyobesity prevalence (27) Samoans Hawaiians CubansPuerto Ricans non-Hispanic Whites Blacks and AIANswere significantly more likely to experience excess weightgain (gt40 pounds) during pregnancy compared to womenin all Asian subgroups Approximately 223 of AIANsand 149 of non-Hispanic whites reported having smokedbefore pregnancy compared with lt3 of Asian mothersRacialethnic patterns in smoking during pregnancy weresimilar

After controlling for covariates women in allracialethnic groups had significantly higher risks ofmaternalhypertension compared to Chinese women (Table 1 Model2) Compared with Chinese women non-Hispanic whitesAIANs non-Hispanic blacks and Filipinos had respectively19 20 24 and 29 times higher adjusted odds of maternalhypertension Compared with Chinese women MexicansCentral and South Americans Puerto Ricans and Cubanshad respectively 15 16 17 and 18 times higher adjustedodds of maternal hypertension Compared with Chineseimmigrants the adjusted odds of maternal hypertensionwere 21 times higher for US-born Chinese 26 times higherfor black immigrants 35 times higher for US-born blacks17 times higher for non-Hispanic whites 28 times higher forUS-born non-Hispanic whites 35 times higher for Filipinoimmigrants 34 times higher for US-born Filipinos 30times higher for US-born Japanese and 29 times higher forAIANs (Table 2 Model 2) Sociodemographic and medical

International Journal of Hypertension 7

Table3Ra

cialethnicv

ariatio

nin

selected

socialandmedicalris

kfactorsfor

materna

lhypertensionUnitedStates2014-2015

(119873=79

66573)

RaceEthnicity

MaternalA

gege

35Years

Percent

Maternal

Educationge16

Years

Percent

ForeignBo

rnPercent

Gestatio

nal

Diabetes

Percent

Pre-pregnancy

Overw

eight(BM

Ige2

5)Prevalence

()

Pre-pregnancy

Obesity(BMIge

30)

Prevalence

()

Weightg

ainin

pregnancy

(gt40lbs)

Prevalence

()

Smok

ingBe

fore

Pregnancy

Percent

Smok

ingin

Pregnancy

Percent

AllRa

ces

160

306

223

64

508

251

213

105

81

Non

-Hisp

anicWhite

163

396

66

57

473

231

240

149

116

Non

-Hisp

anicBlack

128

159

150

56

618

350

217

9069

American

IndianA

N100

9216

100

631

360

228

223

179

Chinese

316

675

875

95143

27

147

04

02

Japanese

494

665

725

62

163

48

7721

09

Filip

ino

319

531

727

119

363

117

160

23

12As

ianIndian

187

783

899

133

377

98130

03

02

Korean

365

767

787

79199

50

141

26

14Vietnamese

292

399

813

116

158

36

129

1006

Haw

aiian

145

181

44

83

650

372

248

147

123

Samoan

120

74296

101

876

644

312

9981

Mexican

145

91492

76593

291

155

24

15Pu

erto

Rican

120

154

132

67

568

299

223

101

68

Cuban

170

266

519

52

471

199

257

35

23

CentralSou

thAmerican

208

175

828

64

520

205

149

1206

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafilesA

N=AlaskaN

ative

8 International Journal of Hypertension

risk factors accounted for 63 of racialethnic disparitiesand 46 of ethnic-immigrant disparities in maternalhypertension based on comparison of the disparity indicesfor the unadjusted and adjusted prevalence estimates (datanot shown)

Table 1 shows variation in the prevalence and odds ofmaternal hypertension according to other sociodemographiccharacteristics Increasing maternal age unmarried statusUS-born status lower education nonmetropolitan residenceresidence in the Southern United States prepregnancy obe-sity excess weight gain during pregnancy and gestationaldiabetes were all associated with increased risks of maternalhypertensionWomen aged 40ndash44 andge45 years had respec-tively 17 and 25 times higher adjusted odds of maternalhypertension than those aged lt20 years Women with ges-tational diabetes had a 27 times higher prevalence and 24times higher adjusted odds of maternal hypertension thanthose who did not have gestational diabetes Compared towomen with normal weight (BMI lt 25) overweight womenas well as women with grade 1 and grade 2 obesity hadrespectively 17 27 and 46 times higher adjusted odds ofmaternal hypertension Women who gained gt40 pounds had94 higher adjusted odds of maternal hypertension thanthose who gained lt16 pounds during pregnancy Women inthe Southeastern and SouthwesternUnited States had 33ndash35higher adjusted odds of maternal hypertension than thoseliving in the Pacific region Although smoking during andbefore pregnancy was associated with 10 and 18 higherodds of maternal hypertension respectively after controllingfor sociodemographic and medical risk factors smoking wasfound to be not significantly related tomaternal hypertension(data not shown)

Racialethnic and ethnic-immigrant disparities in preg-nancy-related hypertension and chronic hypertension pre-sented in Tables 4 and 5 respectively generally show patternssimilar to those for the combined outcome ofmaternal hyper-tension However the effect-sizes for some risk factors suchas maternal age prepregnancy BMI smoking during andbefore pregnancy education and geographic residence werestronger for chronic hypertension than for pregnancy-relatedhypertension (data not shown for brevity) For examplecompared to those aged lt20 years women aged 40ndash44 andge45 years had respectively 88 and 120 times higher adjustedodds of chronic hypertension and 11 and 16 times higheradjusted odds of pregnancy-related hypertension Grade 1and grade 2 prepregnancy obesity were associated with 37and 78 times higher adjusted odds of chronic hypertensionand 25 and 37 times higher adjusted odds of pregnancy-related hypertension While maternal education was notsignificantly related to pregnancy-related hypertension aftercontrolling for other covariates there was a consistentand inverse educational gradient in chronic hypertensionWomen with less than a high school education had 30higher adjusted odds of chronic hypertension than those witha college degree Women in the Southeastern United Stateshad 87 higher adjusted odds and those in the New Englandregion had 62higher adjusted odds of chronic hypertensionthan those living in the Pacific region While smoking wasnot significantly related to pregnancy-related hypertension

smoking before and during pregnancy was associated with30ndash33higher risks of chronic hypertension Smoking beforeor during pregnancy was associated with 58-59 higher age-adjusted odds of chronic hypertension and 17-18 highercovariate-adjusted odds of chronic hypertension

Racialethnic variations in eclampsia were similar tothose for chronic andpregnancy-related hypertension Preva-lence of eclampsia was the highest among Samoan HawaiianNon-Hispanic black AIAN and Filipino women and thelowest among Chinese Vietnamese and Korean women(Figure 1) Compared with Chinese women blacks JapaneseSamoans Filipinos and Hawaiians had 3 to 4 times higheradjusted odds of eclampsia (data not shown) Immigrantwomen in most racialethnic groups had a lower risk ofeclampsia than their US-born counterparts The rate ofeclampsia ranged from 06 per 1000 live births for Chineseimmigrant women to 52 for Hawaiians and 53 per 1000 livebirths for Samoans (Figure 1) Chinese immigrants had 47lower adjusted odds than US-born Chinese Japanese immi-grants had 72 lower adjusted odds than US-born Japaneseblack immigrants had 17 lower adjusted odds thanUS-bornblacks and white immigrants had 19 lower adjusted odds ofeclampsia than US-born whites (data not shown) Maternalage lt 20 and ge45 years was associated with substantiallyincreased risks of eclampsia Women in the Southeast regionhad 23 times higher adjusted odds of eclampsia than those inthe Pacific region Gestational diabetes grade 1 prepregnancyobesity and grade 2 prepregnancy obesity were associatedwith 20 20 and 27 times higher adjusted odds of eclampsiarespectively (data not shown)

4 Discussion

To our knowledge this is the largest population-based studyof maternal hypertension in the United States The resultsof this national study indicate substantial racialethnic andnativity differences in the risk of maternal hypertensionwhich were only partially explained by differences in mater-nal age education prepregnancy BMI weight gain duringpregnancy gestational diabetes and other relevant sociode-mographic characteristics The detailed analysis of maternalhypertension prevalence among specific API and Hispanicsubgroups as well as among a large number of immigrantgroups is a particularly novel feature of our study Theincreased risks ofmaternal hypertension amongAIANs non-Hispanic whites blacks and Puerto Ricans are consistentwith those reported in previous US studies [6 8 10ndash12]Significantly higher risks of maternal hypertension amongFilipinos Samoans and Hawaiians and lower risks amongother Asian groups such as Chinese Japanese Koreans andVietnamese reported in our study are consistent with two USstudies conducted in Hawaii and New York City that showsimilar racialethnic patterns in maternal hypertension andpreeclampsia [8 13] Our findings of lower risks of maternalhypertension among Mexicans Cubans and CentralSouthAmericans are compatible with previous studies that showlower risks of hypertension among Hispanics compared tonon-Hispanic whites but higher risks amongHispanics whencompared to Asian groups [4 8 11 12]

International Journal of Hypertension 9

Table 4 Observed prevalence and adjusted odds of pregnancy-related hypertension among 17 racialethnic and 31 ethnic-immigrant groupsUnited States 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 567 322lowast 348 333 364 196 187 205Non-Hispanic Black 655 372lowast 408 390 426 205 196 215American IndianAlaska Native 677 385lowast 425 404 448 196 186 207Chinese 176 100 100 Reference 100 ReferenceJapanese 269 153lowast 147 132 165 150 134 168Filipino 587 334lowast 348 330 368 274 259 289Hawaiian 562 319lowast 346 281 427 167 135 207Asian Indian 326 185lowast 194 184 205 156 148 164Korean 277 157lowast 158 145 171 146 135 159Vietnamese 242 138lowast 138 128 150 131 122 142Samoan 681 387lowast 429 378 486 166 146 189Other AsianPacific Islander 350 199lowast 209 198 220 155 147 163Mexican 428 243lowast 259 248 271 156 149 163Puerto Rican 473 269lowast 290 276 305 167 158 175Cuban 477 271lowast 290 272 308 188 176 200Central amp South American 359 204lowast 213 203 223 164 156 172Other Hispanic 486 276lowast 297 284 311 172 164 180Ethnic-immigrant statusNon-Hispanic White US-born 584 382lowast 420 441 400 263 277 251Non-Hispanic White immigrant 330 216lowast 222 228 216 173 178 168Non-Hispanic Black US-born 683 446lowast 506 526 486 272 283 261Non-Hispanic Black immigrant 491 321lowast 335 344 326 234 241 228American IndianAlaska Native 677 442lowast 500 510 490 260 266 255Chinese US-born 337 220lowast 223 214 233 202 194 211Chinese immigrant 153 100 100 Reference 100 ReferenceJapanese US-born 475 310lowast 311 281 343 269 244 298Japanese immigrant 192 125lowast 118 107 130 133 122 146Hawaiian 562 367lowast 405 346 473 220 188 258Filipino US-born 609 398lowast 428 421 434 308 304 313Filipino immigrant 579 378lowast 393 396 390 324 328 322Asian Indian US-born 374 244lowast 255 244 265 199 191 207Asian Indian immigrant 320 209lowast 221 225 218 173 176 171Korean US-born 291 190lowast 195 176 215 172 156 190Korean immigrant 275 180lowast 179 173 184 170 165 175Vietnamese US-born 377 246lowast 266 248 285 213 199 229Vietnamese immigrant 210 137lowast 137 133 141 136 132 139Samoan 681 445lowast 503 468 539 209 195 224Other AsianPacific Islander US-born 405 265lowast 287 288 286 196 197 195Other AsianPacific Islander immigrant 318 208lowast 217 219 215 178 180 176Mexican US-born 482 315lowast 350 363 338 200 207 193Mexican immigrant 372 243lowast 258 266 249 181 188 175Puerto Rican mainland US-born 469 307lowast 338 345 330 216 220 211Puerto Rican Puerto Rico-born 509 333lowast 363 357 370 228 225 233Cuban US-born 492 322lowast 351 345 357 221 218 225Cuban immigrant 464 303lowast 326 321 331 239 236 243Central amp South American US-born 422 276lowast 302 302 300 195 196 194Central amp South American immigrant 346 226lowast 237 243 231 188 193 183Other Hispanic US-born 499 326lowast 363 373 352 213 220 208Other Hispanic immigrant 455 297lowast 317 322 312 235 239 232All other ethnic-nativity groups 523 342lowast 371 364 377 265 261 270OR = odds ratio CI = confidence interval lowastStatistically significant at 119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that forthe reference group 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region ofresidence gestational diabetes prepregnancy BMI and gestational weight gain Source Data derived from the 2014-2015 US National Natality data files

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

4 International Journal of Hypertension

Table1Con

tinued

Covariate

Num

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SENa

tivity

immigrant

status

USbo

rn6176861

761

165lowast

184

183

186

129

128

130

663

001

Foreignbo

rn17

71387

460

100

100

Reference

100

Reference

510

002

Materna

ledu

catio

n(years)

lt121134548

594

091lowast

102

101

103

092

091

093

659

003

1219

25949

703

108lowast

125

124

126

098

097

099

708

002

13ndash15

22570

33809

124lowast

141

140

142

106

106

107

761

002

ge162343837

650

100

100

Reference

100

Reference

713

002

Plurality

Sing

le76

89433

670

100

100

Reference

100

Reference

616

001

Multip

le277140

1373

205lowast

212

209

214

182

180

184

1066

006

Gestatio

naldiabetes

No

7446

975

626

100

100

Reference

100

Reference

569

001

Yes

508788

1709

287lowast

295

293

297

244

242

246

1324

005

Pre-pregnancyB

MI

Normatweight(BM

Ilt25)

36796

45395

100

100

Reference

100

Reference

354

001

Overw

eight(25leB

MIlt

30)

1923934

686

174lowast

178

177

180

174

173

176

583

002

Obesitygrade1

(30leB

MIlt

35)

1034214

1026

260lowast

277

275

280

269

267

271

845

003

Obesitygrade2

(BMIge

35)

846413

1674

424lowast

491

487

495

460

456

464

1122

005

Weig

htgain

durin

gpregnancy

(lbs)

lt161166852

796

100

100

Reference

100

Reference

541

002

16ndash30

2938813

588

074lowast

110

109

110

112

111

113

577

001

31ndash4

018

99825

605

076lowast

132

130

133

132

131

134

657

002

gt4016

24798

916

115lowast

204

202

206

194

192

195

925

002

Placeo

fresidence

Metropo

litan

coun

ty6353967

668

100

100

Reference

100

Reference

627

001

Non

-metropo

litan

coun

ty16

12606

798

119lowast

127

126

128

104

104

105

657

002

Region

ofresid

ence

New

England

2993

20612

115lowast

115

113

117

110

108

111

555

004

Mid

Atlantic

965794

625

118lowast

119

118

120

110

109

111

524

002

EastNorthcentral

1125412

796

150lowast

160

158

162

124

123

126

669

002

WestN

orthcentral

548470

752

142lowast

151

149

153

119

117

121

636

003

SouthAtlantic

1499665

716

135lowast

142

140

143

115

114

116

640

002

EastSouthcentral

4716

37887

167lowast

185

183

188

135

133

137

777

004

WestS

outhcentral

1116431

751

142lowast

152

151

154

133

132

135

730

003

Mou

ntain

616787

653

123lowast

129

128

131

119

117

120

649

003

Pacific

1323057

530

100

100

Reference

100

Reference

550

002

OR=od

dsratio

CI=

confi

denceintervallowastStatisticallysig

nificantat119901lt0051Definedas

ther

atio

ofthep

revalencefor

aspecificg

roup

tothatforthe

referenceg

roup

2Ad

juste

dform

aternalage

onlyw

eight

gain

odds

werea

djustedform

aternalage

andprepregn

ancy

BMI3Ad

juste

dform

aternalagem

arita

lstatusnativ

itypluralitymaternaledu

catio

nplacea

ndregion

ofresid

encegestatio

naldiabetesprepregn

ancy

BMIandgestationalw

eightg

ain

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafiles

International Journal of Hypertension 5

Table2Observedprevalence

andadjuste

dod

dsof

materna

lhypertensionam

ong32

ethn

ic-im

migrant

grou

psU

nitedStates2014-2015

(119873=79

66573)

Ethn

ic-im

migrant

grou

pNum

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SENon

-Hisp

anicWhiteU

S-bo

rn40319

03739

397lowast

473

452

495

277

265

290

741

001

Non

-Hisp

anicWhiteimmigrant

282556

408

219lowast

232

221

243

173

165

182

485

004

Non

-Hisp

anicBlackUS-bo

rn10

04997

1030

554lowast

727

694

761

347

331

364

901

003

Non

-Hisp

anicBlackim

migrant

1772

9970

8381lowast

413

393

434

263

250

276

707

006

American

IndianA

laskaN

ative

75204

893

480lowast

619

587

652

286

271

301

761

009

ChineseUS-bo

rn14497

425

228lowast

231

210

253

212

193

233

583

022

Chineseim

migrant

1017

5318

610

010

0Re

ference

100

Reference

293

006

JapaneseU

S-bo

rn3893

645

347lowast

343

300

393

302

263

346

798

046

Japaneseimmigrant

10270

232

125lowast

112

098

128

128

111

146

368

023

Haw

aiian

1725

696

374lowast

449

371

543

223

184

271

611

053

Filip

inoUS-bo

rn17216

799

430lowast

483

449

518

343

319

369

891

022

Filip

inoim

migrant

45845

763

410lowast

433

409

458

353

333

373

913

014

AsianIndianU

S-bo

rn1332

3452

243lowast

257

234

282

196

179

216

545

021

AsianIndianimmigrant

118026

391

210lowast

231

218

243

175

165

184

490

007

KoreanU

S-bo

rn6296

381

205lowast

211

184

242

189

165

217

526

032

Koreanimmigrant

2331

3355

191lowast

187

172

203

178

164

194

500

016

VietnameseUS-bo

rn77

13455

245lowast

279

248

313

222

197

249

607

030

Vietnameseim

migrant

33453

256

138lowast

137

126

148

132

122

143

379

012

Samoan

4316

860

462lowast

581

517

652

214

190

241

589

030

Other

AsianPacific

Island

erU

S-bo

rn51424

511

275lowast

323

305

343

209

197

222

577

011

Other

AsianPacific

Island

erimmigrant

87782

405

217lowast

237

224

250

178

168

188

498

008

MexicanU

S-bo

rn554774

579

312lowast

395

376

413

206

196

216

569

003

Mexicanimmigrant

536471

451

243lowast

272

260

285

170

162

179

479

003

Puerto

Rican

mainlandUS-bo

rn1215

54626

336lowast

416

396

438

234

222

246

637

007

Puerto

Rican

Puerto

Rico-born

1853

070

4379lowast

458

426

492

255

237

274

688

018

Cuban

US-bo

rn19864

616

331lowast

391

363

420

229

213

247

626

017

Cuban

immigrant

21389

559

300lowast

343

319

370

234

217

252

637

017

CentralampSouthAmericanU

S-bo

rn47914

530

285lowast

347

327

369

208

195

221

573

011

CentralampSouthAmericanimmigrant

230721

439

236lowast

260

247

273

184

175

194

514

005

Other

Hisp

anicU

S-bo

rn202960

604

325lowast

410

391

431

221

210

232

606

005

Other

Hisp

anicimmigrant

81468

590

317lowast

361

342

381

241

228

254

654

009

Allothere

thnic-nativ

itygrou

ps1812

4691

371lowast

438

407

471

287

266

309

764

020

OR=od

dsratio

CI=

confi

denceintervallowastStatisticallysig

nificantat119901lt0051Definedas

ther

atioof

thep

revalencefor

aspecific

grou

pto

thatforthe

referenceg

roup

2Ad

juste

dform

aternalage

only3Ad

juste

dform

aternalagem

arita

lstatuspluralitym

aternaledu

catio

nplacea

ndregion

ofresid

encegestatio

naldiabetesprepregn

ancy

BMIandgestationalw

eightgainSourceD

atad

erived

fromthe2

014-2015USN

ational

Natality

datafiles

6 International Journal of Hypertension

before and during pregnancy was defined as dichotomousvariables with ldquoyesrdquo and ldquonordquo categories

Prevalence estimates and prevalence ratios were usedto describe the overall association between covariates andmaternal hypertension Prevalence ratio was defined as theratio of the prevalence for a specific group to that for thereference group Multivariable logistic regression was usedto model the adjusted association between each sociodemo-graphic characteristic and the risk of maternal hypertensionpregnancy-related hypertension chronic hypertension oreclampsia [20] In estimating the odds of hypertension forraceethnicity and ethnic-immigrant status we consideredChinese women or Chinese immigrant women as the refer-ence group based on prior research and because they had thelowest prevalence which could potentially be achievable byother population subgroups [11 21 22] Fitted logistic modelswere used to derive adjusted hypertension prevalence atmeanvalues of the covariates [20 21]

An index of disparity which approximated in relativeterms the average deviation of the rates from the rate for thebest-off racialethnic or ethnic-nativity group was used tosummarize hypertension disparities across all groups [23 24]This relativemean deviation index of disparity was calculatedas

ID = (sum119894 1003816100381610038161003816119867119903119894 minus 1198671199031198971003816100381610038161003816 119868)119867119903119897 times 100 119867119903119897 gt 0 (1)

where 119867119903119894 is the hypertension prevalence for the 119894th group(119894 = 1 2 3 31) 119867119903119897 is the prevalence for the group withthe lowest prevalence (ie Chinese women) and 119868 is thenumber of racialethnic (17) or ethnic-immigrant groups (31)being compared [20]

3 Results

During 2014-2015 the overall prevalence of maternal hyper-tension in the US was 69 About 53 of women hadpregnancy-related hypertension and 16 had chronic hyper-tension Substantial racialethnic differences existed in theprevalence of maternal hypertension ranging from 22for Chinese and 29 for Vietnamese women to 89 forAmerican IndiansAlaska Natives (AIANs) and 98 fornon-Hispanic blacks (Table 1) Compared to non-Hispanicwhite women other Asian groups such as Japanese Kore-ans and Asian Indians had significantly lower prevalencewhile Filipinos Samoans AIANs and non-Hispanic blackshad significantly higher prevalence Compared to Chinesewomen women in all other racialethnic groups had signif-icantly higher risks of maternal hypertension Among APIwomen Samoans Filipinos and Hawaiians had the highestprevalence of maternal hypertension Among HispanicsPuerto Ricans had the highest prevalence (64) followedby Cubans Mexicans and Central and South AmericansHowever the prevalence for all Hispanic subgroups wassignificantly lower than the prevalence of 72 for non-Hispanic whites (Table 1)

Immigrant women in most racialethnic groups hadlower rates of maternal hypertension than their US-born

counterparts with the prevalence ranging from 19 forChinese immigrants and 23 for Japanese immigrants to103 for US-born blacks (Table 2) For example Chineseimmigrants had a 56 lower risk of maternal hypertensionthan US-born Chinese Vietnamese immigrants had a 44lower risk thanUS-born Vietnamese black immigrants had a31 lower risk thanUS-born blacksMexican immigrants hada 22 lower risk than US-born Mexicans and non-Hispanicwhite immigrants had a 45 lower risk than US-born non-Hispanic whites

Racialethnic groups varied greatly in their sociodemo-graphic and medical characteristics known to be associatedwith maternal hypertension (Table 3) For example whilelt13 of births occurred among AIAN Puerto Rican andblackmothers agedge35 years this percentagewas 32amongChinese and Filipinos 37 among Koreans and 49 amongJapanese mothers Educational attainment was the highestamong Asian Indian and Korean women and the lowestamong Mexican and Samoan women The percentage ofmothers with a college degree ranged from 767 for Koreansand 783 for Asian Indians to 74 for Samoans 91 forMexicans and 92 for AIANs More than 87 of Chineseand Asian Indian mothers were foreign-born comparedwith 66 of non-Hispanic whites and 150 of blacksThe prevalence of gestational diabetes was 133 for AsianIndians 119 for Filipinos 116 for Vietnamese 101 forSamoans 10 for AIANs and 95 for Chinese comparedwith 56 for blacks and 57 for non-Hispanic whitesSamoan women had the highest prevalence of prepregnancyobesity (644) followed by Hawaiians (372) AIANs(360) blacks (350) Puerto Ricans (299) and Mexi-cans (291) Chinese women had the lowest prepregnancyobesity prevalence (27) Samoans Hawaiians CubansPuerto Ricans non-Hispanic Whites Blacks and AIANswere significantly more likely to experience excess weightgain (gt40 pounds) during pregnancy compared to womenin all Asian subgroups Approximately 223 of AIANsand 149 of non-Hispanic whites reported having smokedbefore pregnancy compared with lt3 of Asian mothersRacialethnic patterns in smoking during pregnancy weresimilar

After controlling for covariates women in allracialethnic groups had significantly higher risks ofmaternalhypertension compared to Chinese women (Table 1 Model2) Compared with Chinese women non-Hispanic whitesAIANs non-Hispanic blacks and Filipinos had respectively19 20 24 and 29 times higher adjusted odds of maternalhypertension Compared with Chinese women MexicansCentral and South Americans Puerto Ricans and Cubanshad respectively 15 16 17 and 18 times higher adjustedodds of maternal hypertension Compared with Chineseimmigrants the adjusted odds of maternal hypertensionwere 21 times higher for US-born Chinese 26 times higherfor black immigrants 35 times higher for US-born blacks17 times higher for non-Hispanic whites 28 times higher forUS-born non-Hispanic whites 35 times higher for Filipinoimmigrants 34 times higher for US-born Filipinos 30times higher for US-born Japanese and 29 times higher forAIANs (Table 2 Model 2) Sociodemographic and medical

International Journal of Hypertension 7

Table3Ra

cialethnicv

ariatio

nin

selected

socialandmedicalris

kfactorsfor

materna

lhypertensionUnitedStates2014-2015

(119873=79

66573)

RaceEthnicity

MaternalA

gege

35Years

Percent

Maternal

Educationge16

Years

Percent

ForeignBo

rnPercent

Gestatio

nal

Diabetes

Percent

Pre-pregnancy

Overw

eight(BM

Ige2

5)Prevalence

()

Pre-pregnancy

Obesity(BMIge

30)

Prevalence

()

Weightg

ainin

pregnancy

(gt40lbs)

Prevalence

()

Smok

ingBe

fore

Pregnancy

Percent

Smok

ingin

Pregnancy

Percent

AllRa

ces

160

306

223

64

508

251

213

105

81

Non

-Hisp

anicWhite

163

396

66

57

473

231

240

149

116

Non

-Hisp

anicBlack

128

159

150

56

618

350

217

9069

American

IndianA

N100

9216

100

631

360

228

223

179

Chinese

316

675

875

95143

27

147

04

02

Japanese

494

665

725

62

163

48

7721

09

Filip

ino

319

531

727

119

363

117

160

23

12As

ianIndian

187

783

899

133

377

98130

03

02

Korean

365

767

787

79199

50

141

26

14Vietnamese

292

399

813

116

158

36

129

1006

Haw

aiian

145

181

44

83

650

372

248

147

123

Samoan

120

74296

101

876

644

312

9981

Mexican

145

91492

76593

291

155

24

15Pu

erto

Rican

120

154

132

67

568

299

223

101

68

Cuban

170

266

519

52

471

199

257

35

23

CentralSou

thAmerican

208

175

828

64

520

205

149

1206

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafilesA

N=AlaskaN

ative

8 International Journal of Hypertension

risk factors accounted for 63 of racialethnic disparitiesand 46 of ethnic-immigrant disparities in maternalhypertension based on comparison of the disparity indicesfor the unadjusted and adjusted prevalence estimates (datanot shown)

Table 1 shows variation in the prevalence and odds ofmaternal hypertension according to other sociodemographiccharacteristics Increasing maternal age unmarried statusUS-born status lower education nonmetropolitan residenceresidence in the Southern United States prepregnancy obe-sity excess weight gain during pregnancy and gestationaldiabetes were all associated with increased risks of maternalhypertensionWomen aged 40ndash44 andge45 years had respec-tively 17 and 25 times higher adjusted odds of maternalhypertension than those aged lt20 years Women with ges-tational diabetes had a 27 times higher prevalence and 24times higher adjusted odds of maternal hypertension thanthose who did not have gestational diabetes Compared towomen with normal weight (BMI lt 25) overweight womenas well as women with grade 1 and grade 2 obesity hadrespectively 17 27 and 46 times higher adjusted odds ofmaternal hypertension Women who gained gt40 pounds had94 higher adjusted odds of maternal hypertension thanthose who gained lt16 pounds during pregnancy Women inthe Southeastern and SouthwesternUnited States had 33ndash35higher adjusted odds of maternal hypertension than thoseliving in the Pacific region Although smoking during andbefore pregnancy was associated with 10 and 18 higherodds of maternal hypertension respectively after controllingfor sociodemographic and medical risk factors smoking wasfound to be not significantly related tomaternal hypertension(data not shown)

Racialethnic and ethnic-immigrant disparities in preg-nancy-related hypertension and chronic hypertension pre-sented in Tables 4 and 5 respectively generally show patternssimilar to those for the combined outcome ofmaternal hyper-tension However the effect-sizes for some risk factors suchas maternal age prepregnancy BMI smoking during andbefore pregnancy education and geographic residence werestronger for chronic hypertension than for pregnancy-relatedhypertension (data not shown for brevity) For examplecompared to those aged lt20 years women aged 40ndash44 andge45 years had respectively 88 and 120 times higher adjustedodds of chronic hypertension and 11 and 16 times higheradjusted odds of pregnancy-related hypertension Grade 1and grade 2 prepregnancy obesity were associated with 37and 78 times higher adjusted odds of chronic hypertensionand 25 and 37 times higher adjusted odds of pregnancy-related hypertension While maternal education was notsignificantly related to pregnancy-related hypertension aftercontrolling for other covariates there was a consistentand inverse educational gradient in chronic hypertensionWomen with less than a high school education had 30higher adjusted odds of chronic hypertension than those witha college degree Women in the Southeastern United Stateshad 87 higher adjusted odds and those in the New Englandregion had 62higher adjusted odds of chronic hypertensionthan those living in the Pacific region While smoking wasnot significantly related to pregnancy-related hypertension

smoking before and during pregnancy was associated with30ndash33higher risks of chronic hypertension Smoking beforeor during pregnancy was associated with 58-59 higher age-adjusted odds of chronic hypertension and 17-18 highercovariate-adjusted odds of chronic hypertension

Racialethnic variations in eclampsia were similar tothose for chronic andpregnancy-related hypertension Preva-lence of eclampsia was the highest among Samoan HawaiianNon-Hispanic black AIAN and Filipino women and thelowest among Chinese Vietnamese and Korean women(Figure 1) Compared with Chinese women blacks JapaneseSamoans Filipinos and Hawaiians had 3 to 4 times higheradjusted odds of eclampsia (data not shown) Immigrantwomen in most racialethnic groups had a lower risk ofeclampsia than their US-born counterparts The rate ofeclampsia ranged from 06 per 1000 live births for Chineseimmigrant women to 52 for Hawaiians and 53 per 1000 livebirths for Samoans (Figure 1) Chinese immigrants had 47lower adjusted odds than US-born Chinese Japanese immi-grants had 72 lower adjusted odds than US-born Japaneseblack immigrants had 17 lower adjusted odds thanUS-bornblacks and white immigrants had 19 lower adjusted odds ofeclampsia than US-born whites (data not shown) Maternalage lt 20 and ge45 years was associated with substantiallyincreased risks of eclampsia Women in the Southeast regionhad 23 times higher adjusted odds of eclampsia than those inthe Pacific region Gestational diabetes grade 1 prepregnancyobesity and grade 2 prepregnancy obesity were associatedwith 20 20 and 27 times higher adjusted odds of eclampsiarespectively (data not shown)

4 Discussion

To our knowledge this is the largest population-based studyof maternal hypertension in the United States The resultsof this national study indicate substantial racialethnic andnativity differences in the risk of maternal hypertensionwhich were only partially explained by differences in mater-nal age education prepregnancy BMI weight gain duringpregnancy gestational diabetes and other relevant sociode-mographic characteristics The detailed analysis of maternalhypertension prevalence among specific API and Hispanicsubgroups as well as among a large number of immigrantgroups is a particularly novel feature of our study Theincreased risks ofmaternal hypertension amongAIANs non-Hispanic whites blacks and Puerto Ricans are consistentwith those reported in previous US studies [6 8 10ndash12]Significantly higher risks of maternal hypertension amongFilipinos Samoans and Hawaiians and lower risks amongother Asian groups such as Chinese Japanese Koreans andVietnamese reported in our study are consistent with two USstudies conducted in Hawaii and New York City that showsimilar racialethnic patterns in maternal hypertension andpreeclampsia [8 13] Our findings of lower risks of maternalhypertension among Mexicans Cubans and CentralSouthAmericans are compatible with previous studies that showlower risks of hypertension among Hispanics compared tonon-Hispanic whites but higher risks amongHispanics whencompared to Asian groups [4 8 11 12]

International Journal of Hypertension 9

Table 4 Observed prevalence and adjusted odds of pregnancy-related hypertension among 17 racialethnic and 31 ethnic-immigrant groupsUnited States 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 567 322lowast 348 333 364 196 187 205Non-Hispanic Black 655 372lowast 408 390 426 205 196 215American IndianAlaska Native 677 385lowast 425 404 448 196 186 207Chinese 176 100 100 Reference 100 ReferenceJapanese 269 153lowast 147 132 165 150 134 168Filipino 587 334lowast 348 330 368 274 259 289Hawaiian 562 319lowast 346 281 427 167 135 207Asian Indian 326 185lowast 194 184 205 156 148 164Korean 277 157lowast 158 145 171 146 135 159Vietnamese 242 138lowast 138 128 150 131 122 142Samoan 681 387lowast 429 378 486 166 146 189Other AsianPacific Islander 350 199lowast 209 198 220 155 147 163Mexican 428 243lowast 259 248 271 156 149 163Puerto Rican 473 269lowast 290 276 305 167 158 175Cuban 477 271lowast 290 272 308 188 176 200Central amp South American 359 204lowast 213 203 223 164 156 172Other Hispanic 486 276lowast 297 284 311 172 164 180Ethnic-immigrant statusNon-Hispanic White US-born 584 382lowast 420 441 400 263 277 251Non-Hispanic White immigrant 330 216lowast 222 228 216 173 178 168Non-Hispanic Black US-born 683 446lowast 506 526 486 272 283 261Non-Hispanic Black immigrant 491 321lowast 335 344 326 234 241 228American IndianAlaska Native 677 442lowast 500 510 490 260 266 255Chinese US-born 337 220lowast 223 214 233 202 194 211Chinese immigrant 153 100 100 Reference 100 ReferenceJapanese US-born 475 310lowast 311 281 343 269 244 298Japanese immigrant 192 125lowast 118 107 130 133 122 146Hawaiian 562 367lowast 405 346 473 220 188 258Filipino US-born 609 398lowast 428 421 434 308 304 313Filipino immigrant 579 378lowast 393 396 390 324 328 322Asian Indian US-born 374 244lowast 255 244 265 199 191 207Asian Indian immigrant 320 209lowast 221 225 218 173 176 171Korean US-born 291 190lowast 195 176 215 172 156 190Korean immigrant 275 180lowast 179 173 184 170 165 175Vietnamese US-born 377 246lowast 266 248 285 213 199 229Vietnamese immigrant 210 137lowast 137 133 141 136 132 139Samoan 681 445lowast 503 468 539 209 195 224Other AsianPacific Islander US-born 405 265lowast 287 288 286 196 197 195Other AsianPacific Islander immigrant 318 208lowast 217 219 215 178 180 176Mexican US-born 482 315lowast 350 363 338 200 207 193Mexican immigrant 372 243lowast 258 266 249 181 188 175Puerto Rican mainland US-born 469 307lowast 338 345 330 216 220 211Puerto Rican Puerto Rico-born 509 333lowast 363 357 370 228 225 233Cuban US-born 492 322lowast 351 345 357 221 218 225Cuban immigrant 464 303lowast 326 321 331 239 236 243Central amp South American US-born 422 276lowast 302 302 300 195 196 194Central amp South American immigrant 346 226lowast 237 243 231 188 193 183Other Hispanic US-born 499 326lowast 363 373 352 213 220 208Other Hispanic immigrant 455 297lowast 317 322 312 235 239 232All other ethnic-nativity groups 523 342lowast 371 364 377 265 261 270OR = odds ratio CI = confidence interval lowastStatistically significant at 119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that forthe reference group 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region ofresidence gestational diabetes prepregnancy BMI and gestational weight gain Source Data derived from the 2014-2015 US National Natality data files

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

International Journal of Hypertension 5

Table2Observedprevalence

andadjuste

dod

dsof

materna

lhypertensionam

ong32

ethn

ic-im

migrant

grou

psU

nitedStates2014-2015

(119873=79

66573)

Ethn

ic-im

migrant

grou

pNum

bero

fbirths

Prevalence

percent

Prevalence

ratio1

Mod

el12

Mod

el23

Covariance-adjuste

dOR

95CI

OR

95CI

prevalence

SENon

-Hisp

anicWhiteU

S-bo

rn40319

03739

397lowast

473

452

495

277

265

290

741

001

Non

-Hisp

anicWhiteimmigrant

282556

408

219lowast

232

221

243

173

165

182

485

004

Non

-Hisp

anicBlackUS-bo

rn10

04997

1030

554lowast

727

694

761

347

331

364

901

003

Non

-Hisp

anicBlackim

migrant

1772

9970

8381lowast

413

393

434

263

250

276

707

006

American

IndianA

laskaN

ative

75204

893

480lowast

619

587

652

286

271

301

761

009

ChineseUS-bo

rn14497

425

228lowast

231

210

253

212

193

233

583

022

Chineseim

migrant

1017

5318

610

010

0Re

ference

100

Reference

293

006

JapaneseU

S-bo

rn3893

645

347lowast

343

300

393

302

263

346

798

046

Japaneseimmigrant

10270

232

125lowast

112

098

128

128

111

146

368

023

Haw

aiian

1725

696

374lowast

449

371

543

223

184

271

611

053

Filip

inoUS-bo

rn17216

799

430lowast

483

449

518

343

319

369

891

022

Filip

inoim

migrant

45845

763

410lowast

433

409

458

353

333

373

913

014

AsianIndianU

S-bo

rn1332

3452

243lowast

257

234

282

196

179

216

545

021

AsianIndianimmigrant

118026

391

210lowast

231

218

243

175

165

184

490

007

KoreanU

S-bo

rn6296

381

205lowast

211

184

242

189

165

217

526

032

Koreanimmigrant

2331

3355

191lowast

187

172

203

178

164

194

500

016

VietnameseUS-bo

rn77

13455

245lowast

279

248

313

222

197

249

607

030

Vietnameseim

migrant

33453

256

138lowast

137

126

148

132

122

143

379

012

Samoan

4316

860

462lowast

581

517

652

214

190

241

589

030

Other

AsianPacific

Island

erU

S-bo

rn51424

511

275lowast

323

305

343

209

197

222

577

011

Other

AsianPacific

Island

erimmigrant

87782

405

217lowast

237

224

250

178

168

188

498

008

MexicanU

S-bo

rn554774

579

312lowast

395

376

413

206

196

216

569

003

Mexicanimmigrant

536471

451

243lowast

272

260

285

170

162

179

479

003

Puerto

Rican

mainlandUS-bo

rn1215

54626

336lowast

416

396

438

234

222

246

637

007

Puerto

Rican

Puerto

Rico-born

1853

070

4379lowast

458

426

492

255

237

274

688

018

Cuban

US-bo

rn19864

616

331lowast

391

363

420

229

213

247

626

017

Cuban

immigrant

21389

559

300lowast

343

319

370

234

217

252

637

017

CentralampSouthAmericanU

S-bo

rn47914

530

285lowast

347

327

369

208

195

221

573

011

CentralampSouthAmericanimmigrant

230721

439

236lowast

260

247

273

184

175

194

514

005

Other

Hisp

anicU

S-bo

rn202960

604

325lowast

410

391

431

221

210

232

606

005

Other

Hisp

anicimmigrant

81468

590

317lowast

361

342

381

241

228

254

654

009

Allothere

thnic-nativ

itygrou

ps1812

4691

371lowast

438

407

471

287

266

309

764

020

OR=od

dsratio

CI=

confi

denceintervallowastStatisticallysig

nificantat119901lt0051Definedas

ther

atioof

thep

revalencefor

aspecific

grou

pto

thatforthe

referenceg

roup

2Ad

juste

dform

aternalage

only3Ad

juste

dform

aternalagem

arita

lstatuspluralitym

aternaledu

catio

nplacea

ndregion

ofresid

encegestatio

naldiabetesprepregn

ancy

BMIandgestationalw

eightgainSourceD

atad

erived

fromthe2

014-2015USN

ational

Natality

datafiles

6 International Journal of Hypertension

before and during pregnancy was defined as dichotomousvariables with ldquoyesrdquo and ldquonordquo categories

Prevalence estimates and prevalence ratios were usedto describe the overall association between covariates andmaternal hypertension Prevalence ratio was defined as theratio of the prevalence for a specific group to that for thereference group Multivariable logistic regression was usedto model the adjusted association between each sociodemo-graphic characteristic and the risk of maternal hypertensionpregnancy-related hypertension chronic hypertension oreclampsia [20] In estimating the odds of hypertension forraceethnicity and ethnic-immigrant status we consideredChinese women or Chinese immigrant women as the refer-ence group based on prior research and because they had thelowest prevalence which could potentially be achievable byother population subgroups [11 21 22] Fitted logistic modelswere used to derive adjusted hypertension prevalence atmeanvalues of the covariates [20 21]

An index of disparity which approximated in relativeterms the average deviation of the rates from the rate for thebest-off racialethnic or ethnic-nativity group was used tosummarize hypertension disparities across all groups [23 24]This relativemean deviation index of disparity was calculatedas

ID = (sum119894 1003816100381610038161003816119867119903119894 minus 1198671199031198971003816100381610038161003816 119868)119867119903119897 times 100 119867119903119897 gt 0 (1)

where 119867119903119894 is the hypertension prevalence for the 119894th group(119894 = 1 2 3 31) 119867119903119897 is the prevalence for the group withthe lowest prevalence (ie Chinese women) and 119868 is thenumber of racialethnic (17) or ethnic-immigrant groups (31)being compared [20]

3 Results

During 2014-2015 the overall prevalence of maternal hyper-tension in the US was 69 About 53 of women hadpregnancy-related hypertension and 16 had chronic hyper-tension Substantial racialethnic differences existed in theprevalence of maternal hypertension ranging from 22for Chinese and 29 for Vietnamese women to 89 forAmerican IndiansAlaska Natives (AIANs) and 98 fornon-Hispanic blacks (Table 1) Compared to non-Hispanicwhite women other Asian groups such as Japanese Kore-ans and Asian Indians had significantly lower prevalencewhile Filipinos Samoans AIANs and non-Hispanic blackshad significantly higher prevalence Compared to Chinesewomen women in all other racialethnic groups had signif-icantly higher risks of maternal hypertension Among APIwomen Samoans Filipinos and Hawaiians had the highestprevalence of maternal hypertension Among HispanicsPuerto Ricans had the highest prevalence (64) followedby Cubans Mexicans and Central and South AmericansHowever the prevalence for all Hispanic subgroups wassignificantly lower than the prevalence of 72 for non-Hispanic whites (Table 1)

Immigrant women in most racialethnic groups hadlower rates of maternal hypertension than their US-born

counterparts with the prevalence ranging from 19 forChinese immigrants and 23 for Japanese immigrants to103 for US-born blacks (Table 2) For example Chineseimmigrants had a 56 lower risk of maternal hypertensionthan US-born Chinese Vietnamese immigrants had a 44lower risk thanUS-born Vietnamese black immigrants had a31 lower risk thanUS-born blacksMexican immigrants hada 22 lower risk than US-born Mexicans and non-Hispanicwhite immigrants had a 45 lower risk than US-born non-Hispanic whites

Racialethnic groups varied greatly in their sociodemo-graphic and medical characteristics known to be associatedwith maternal hypertension (Table 3) For example whilelt13 of births occurred among AIAN Puerto Rican andblackmothers agedge35 years this percentagewas 32amongChinese and Filipinos 37 among Koreans and 49 amongJapanese mothers Educational attainment was the highestamong Asian Indian and Korean women and the lowestamong Mexican and Samoan women The percentage ofmothers with a college degree ranged from 767 for Koreansand 783 for Asian Indians to 74 for Samoans 91 forMexicans and 92 for AIANs More than 87 of Chineseand Asian Indian mothers were foreign-born comparedwith 66 of non-Hispanic whites and 150 of blacksThe prevalence of gestational diabetes was 133 for AsianIndians 119 for Filipinos 116 for Vietnamese 101 forSamoans 10 for AIANs and 95 for Chinese comparedwith 56 for blacks and 57 for non-Hispanic whitesSamoan women had the highest prevalence of prepregnancyobesity (644) followed by Hawaiians (372) AIANs(360) blacks (350) Puerto Ricans (299) and Mexi-cans (291) Chinese women had the lowest prepregnancyobesity prevalence (27) Samoans Hawaiians CubansPuerto Ricans non-Hispanic Whites Blacks and AIANswere significantly more likely to experience excess weightgain (gt40 pounds) during pregnancy compared to womenin all Asian subgroups Approximately 223 of AIANsand 149 of non-Hispanic whites reported having smokedbefore pregnancy compared with lt3 of Asian mothersRacialethnic patterns in smoking during pregnancy weresimilar

After controlling for covariates women in allracialethnic groups had significantly higher risks ofmaternalhypertension compared to Chinese women (Table 1 Model2) Compared with Chinese women non-Hispanic whitesAIANs non-Hispanic blacks and Filipinos had respectively19 20 24 and 29 times higher adjusted odds of maternalhypertension Compared with Chinese women MexicansCentral and South Americans Puerto Ricans and Cubanshad respectively 15 16 17 and 18 times higher adjustedodds of maternal hypertension Compared with Chineseimmigrants the adjusted odds of maternal hypertensionwere 21 times higher for US-born Chinese 26 times higherfor black immigrants 35 times higher for US-born blacks17 times higher for non-Hispanic whites 28 times higher forUS-born non-Hispanic whites 35 times higher for Filipinoimmigrants 34 times higher for US-born Filipinos 30times higher for US-born Japanese and 29 times higher forAIANs (Table 2 Model 2) Sociodemographic and medical

International Journal of Hypertension 7

Table3Ra

cialethnicv

ariatio

nin

selected

socialandmedicalris

kfactorsfor

materna

lhypertensionUnitedStates2014-2015

(119873=79

66573)

RaceEthnicity

MaternalA

gege

35Years

Percent

Maternal

Educationge16

Years

Percent

ForeignBo

rnPercent

Gestatio

nal

Diabetes

Percent

Pre-pregnancy

Overw

eight(BM

Ige2

5)Prevalence

()

Pre-pregnancy

Obesity(BMIge

30)

Prevalence

()

Weightg

ainin

pregnancy

(gt40lbs)

Prevalence

()

Smok

ingBe

fore

Pregnancy

Percent

Smok

ingin

Pregnancy

Percent

AllRa

ces

160

306

223

64

508

251

213

105

81

Non

-Hisp

anicWhite

163

396

66

57

473

231

240

149

116

Non

-Hisp

anicBlack

128

159

150

56

618

350

217

9069

American

IndianA

N100

9216

100

631

360

228

223

179

Chinese

316

675

875

95143

27

147

04

02

Japanese

494

665

725

62

163

48

7721

09

Filip

ino

319

531

727

119

363

117

160

23

12As

ianIndian

187

783

899

133

377

98130

03

02

Korean

365

767

787

79199

50

141

26

14Vietnamese

292

399

813

116

158

36

129

1006

Haw

aiian

145

181

44

83

650

372

248

147

123

Samoan

120

74296

101

876

644

312

9981

Mexican

145

91492

76593

291

155

24

15Pu

erto

Rican

120

154

132

67

568

299

223

101

68

Cuban

170

266

519

52

471

199

257

35

23

CentralSou

thAmerican

208

175

828

64

520

205

149

1206

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafilesA

N=AlaskaN

ative

8 International Journal of Hypertension

risk factors accounted for 63 of racialethnic disparitiesand 46 of ethnic-immigrant disparities in maternalhypertension based on comparison of the disparity indicesfor the unadjusted and adjusted prevalence estimates (datanot shown)

Table 1 shows variation in the prevalence and odds ofmaternal hypertension according to other sociodemographiccharacteristics Increasing maternal age unmarried statusUS-born status lower education nonmetropolitan residenceresidence in the Southern United States prepregnancy obe-sity excess weight gain during pregnancy and gestationaldiabetes were all associated with increased risks of maternalhypertensionWomen aged 40ndash44 andge45 years had respec-tively 17 and 25 times higher adjusted odds of maternalhypertension than those aged lt20 years Women with ges-tational diabetes had a 27 times higher prevalence and 24times higher adjusted odds of maternal hypertension thanthose who did not have gestational diabetes Compared towomen with normal weight (BMI lt 25) overweight womenas well as women with grade 1 and grade 2 obesity hadrespectively 17 27 and 46 times higher adjusted odds ofmaternal hypertension Women who gained gt40 pounds had94 higher adjusted odds of maternal hypertension thanthose who gained lt16 pounds during pregnancy Women inthe Southeastern and SouthwesternUnited States had 33ndash35higher adjusted odds of maternal hypertension than thoseliving in the Pacific region Although smoking during andbefore pregnancy was associated with 10 and 18 higherodds of maternal hypertension respectively after controllingfor sociodemographic and medical risk factors smoking wasfound to be not significantly related tomaternal hypertension(data not shown)

Racialethnic and ethnic-immigrant disparities in preg-nancy-related hypertension and chronic hypertension pre-sented in Tables 4 and 5 respectively generally show patternssimilar to those for the combined outcome ofmaternal hyper-tension However the effect-sizes for some risk factors suchas maternal age prepregnancy BMI smoking during andbefore pregnancy education and geographic residence werestronger for chronic hypertension than for pregnancy-relatedhypertension (data not shown for brevity) For examplecompared to those aged lt20 years women aged 40ndash44 andge45 years had respectively 88 and 120 times higher adjustedodds of chronic hypertension and 11 and 16 times higheradjusted odds of pregnancy-related hypertension Grade 1and grade 2 prepregnancy obesity were associated with 37and 78 times higher adjusted odds of chronic hypertensionand 25 and 37 times higher adjusted odds of pregnancy-related hypertension While maternal education was notsignificantly related to pregnancy-related hypertension aftercontrolling for other covariates there was a consistentand inverse educational gradient in chronic hypertensionWomen with less than a high school education had 30higher adjusted odds of chronic hypertension than those witha college degree Women in the Southeastern United Stateshad 87 higher adjusted odds and those in the New Englandregion had 62higher adjusted odds of chronic hypertensionthan those living in the Pacific region While smoking wasnot significantly related to pregnancy-related hypertension

smoking before and during pregnancy was associated with30ndash33higher risks of chronic hypertension Smoking beforeor during pregnancy was associated with 58-59 higher age-adjusted odds of chronic hypertension and 17-18 highercovariate-adjusted odds of chronic hypertension

Racialethnic variations in eclampsia were similar tothose for chronic andpregnancy-related hypertension Preva-lence of eclampsia was the highest among Samoan HawaiianNon-Hispanic black AIAN and Filipino women and thelowest among Chinese Vietnamese and Korean women(Figure 1) Compared with Chinese women blacks JapaneseSamoans Filipinos and Hawaiians had 3 to 4 times higheradjusted odds of eclampsia (data not shown) Immigrantwomen in most racialethnic groups had a lower risk ofeclampsia than their US-born counterparts The rate ofeclampsia ranged from 06 per 1000 live births for Chineseimmigrant women to 52 for Hawaiians and 53 per 1000 livebirths for Samoans (Figure 1) Chinese immigrants had 47lower adjusted odds than US-born Chinese Japanese immi-grants had 72 lower adjusted odds than US-born Japaneseblack immigrants had 17 lower adjusted odds thanUS-bornblacks and white immigrants had 19 lower adjusted odds ofeclampsia than US-born whites (data not shown) Maternalage lt 20 and ge45 years was associated with substantiallyincreased risks of eclampsia Women in the Southeast regionhad 23 times higher adjusted odds of eclampsia than those inthe Pacific region Gestational diabetes grade 1 prepregnancyobesity and grade 2 prepregnancy obesity were associatedwith 20 20 and 27 times higher adjusted odds of eclampsiarespectively (data not shown)

4 Discussion

To our knowledge this is the largest population-based studyof maternal hypertension in the United States The resultsof this national study indicate substantial racialethnic andnativity differences in the risk of maternal hypertensionwhich were only partially explained by differences in mater-nal age education prepregnancy BMI weight gain duringpregnancy gestational diabetes and other relevant sociode-mographic characteristics The detailed analysis of maternalhypertension prevalence among specific API and Hispanicsubgroups as well as among a large number of immigrantgroups is a particularly novel feature of our study Theincreased risks ofmaternal hypertension amongAIANs non-Hispanic whites blacks and Puerto Ricans are consistentwith those reported in previous US studies [6 8 10ndash12]Significantly higher risks of maternal hypertension amongFilipinos Samoans and Hawaiians and lower risks amongother Asian groups such as Chinese Japanese Koreans andVietnamese reported in our study are consistent with two USstudies conducted in Hawaii and New York City that showsimilar racialethnic patterns in maternal hypertension andpreeclampsia [8 13] Our findings of lower risks of maternalhypertension among Mexicans Cubans and CentralSouthAmericans are compatible with previous studies that showlower risks of hypertension among Hispanics compared tonon-Hispanic whites but higher risks amongHispanics whencompared to Asian groups [4 8 11 12]

International Journal of Hypertension 9

Table 4 Observed prevalence and adjusted odds of pregnancy-related hypertension among 17 racialethnic and 31 ethnic-immigrant groupsUnited States 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 567 322lowast 348 333 364 196 187 205Non-Hispanic Black 655 372lowast 408 390 426 205 196 215American IndianAlaska Native 677 385lowast 425 404 448 196 186 207Chinese 176 100 100 Reference 100 ReferenceJapanese 269 153lowast 147 132 165 150 134 168Filipino 587 334lowast 348 330 368 274 259 289Hawaiian 562 319lowast 346 281 427 167 135 207Asian Indian 326 185lowast 194 184 205 156 148 164Korean 277 157lowast 158 145 171 146 135 159Vietnamese 242 138lowast 138 128 150 131 122 142Samoan 681 387lowast 429 378 486 166 146 189Other AsianPacific Islander 350 199lowast 209 198 220 155 147 163Mexican 428 243lowast 259 248 271 156 149 163Puerto Rican 473 269lowast 290 276 305 167 158 175Cuban 477 271lowast 290 272 308 188 176 200Central amp South American 359 204lowast 213 203 223 164 156 172Other Hispanic 486 276lowast 297 284 311 172 164 180Ethnic-immigrant statusNon-Hispanic White US-born 584 382lowast 420 441 400 263 277 251Non-Hispanic White immigrant 330 216lowast 222 228 216 173 178 168Non-Hispanic Black US-born 683 446lowast 506 526 486 272 283 261Non-Hispanic Black immigrant 491 321lowast 335 344 326 234 241 228American IndianAlaska Native 677 442lowast 500 510 490 260 266 255Chinese US-born 337 220lowast 223 214 233 202 194 211Chinese immigrant 153 100 100 Reference 100 ReferenceJapanese US-born 475 310lowast 311 281 343 269 244 298Japanese immigrant 192 125lowast 118 107 130 133 122 146Hawaiian 562 367lowast 405 346 473 220 188 258Filipino US-born 609 398lowast 428 421 434 308 304 313Filipino immigrant 579 378lowast 393 396 390 324 328 322Asian Indian US-born 374 244lowast 255 244 265 199 191 207Asian Indian immigrant 320 209lowast 221 225 218 173 176 171Korean US-born 291 190lowast 195 176 215 172 156 190Korean immigrant 275 180lowast 179 173 184 170 165 175Vietnamese US-born 377 246lowast 266 248 285 213 199 229Vietnamese immigrant 210 137lowast 137 133 141 136 132 139Samoan 681 445lowast 503 468 539 209 195 224Other AsianPacific Islander US-born 405 265lowast 287 288 286 196 197 195Other AsianPacific Islander immigrant 318 208lowast 217 219 215 178 180 176Mexican US-born 482 315lowast 350 363 338 200 207 193Mexican immigrant 372 243lowast 258 266 249 181 188 175Puerto Rican mainland US-born 469 307lowast 338 345 330 216 220 211Puerto Rican Puerto Rico-born 509 333lowast 363 357 370 228 225 233Cuban US-born 492 322lowast 351 345 357 221 218 225Cuban immigrant 464 303lowast 326 321 331 239 236 243Central amp South American US-born 422 276lowast 302 302 300 195 196 194Central amp South American immigrant 346 226lowast 237 243 231 188 193 183Other Hispanic US-born 499 326lowast 363 373 352 213 220 208Other Hispanic immigrant 455 297lowast 317 322 312 235 239 232All other ethnic-nativity groups 523 342lowast 371 364 377 265 261 270OR = odds ratio CI = confidence interval lowastStatistically significant at 119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that forthe reference group 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region ofresidence gestational diabetes prepregnancy BMI and gestational weight gain Source Data derived from the 2014-2015 US National Natality data files

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

6 International Journal of Hypertension

before and during pregnancy was defined as dichotomousvariables with ldquoyesrdquo and ldquonordquo categories

Prevalence estimates and prevalence ratios were usedto describe the overall association between covariates andmaternal hypertension Prevalence ratio was defined as theratio of the prevalence for a specific group to that for thereference group Multivariable logistic regression was usedto model the adjusted association between each sociodemo-graphic characteristic and the risk of maternal hypertensionpregnancy-related hypertension chronic hypertension oreclampsia [20] In estimating the odds of hypertension forraceethnicity and ethnic-immigrant status we consideredChinese women or Chinese immigrant women as the refer-ence group based on prior research and because they had thelowest prevalence which could potentially be achievable byother population subgroups [11 21 22] Fitted logistic modelswere used to derive adjusted hypertension prevalence atmeanvalues of the covariates [20 21]

An index of disparity which approximated in relativeterms the average deviation of the rates from the rate for thebest-off racialethnic or ethnic-nativity group was used tosummarize hypertension disparities across all groups [23 24]This relativemean deviation index of disparity was calculatedas

ID = (sum119894 1003816100381610038161003816119867119903119894 minus 1198671199031198971003816100381610038161003816 119868)119867119903119897 times 100 119867119903119897 gt 0 (1)

where 119867119903119894 is the hypertension prevalence for the 119894th group(119894 = 1 2 3 31) 119867119903119897 is the prevalence for the group withthe lowest prevalence (ie Chinese women) and 119868 is thenumber of racialethnic (17) or ethnic-immigrant groups (31)being compared [20]

3 Results

During 2014-2015 the overall prevalence of maternal hyper-tension in the US was 69 About 53 of women hadpregnancy-related hypertension and 16 had chronic hyper-tension Substantial racialethnic differences existed in theprevalence of maternal hypertension ranging from 22for Chinese and 29 for Vietnamese women to 89 forAmerican IndiansAlaska Natives (AIANs) and 98 fornon-Hispanic blacks (Table 1) Compared to non-Hispanicwhite women other Asian groups such as Japanese Kore-ans and Asian Indians had significantly lower prevalencewhile Filipinos Samoans AIANs and non-Hispanic blackshad significantly higher prevalence Compared to Chinesewomen women in all other racialethnic groups had signif-icantly higher risks of maternal hypertension Among APIwomen Samoans Filipinos and Hawaiians had the highestprevalence of maternal hypertension Among HispanicsPuerto Ricans had the highest prevalence (64) followedby Cubans Mexicans and Central and South AmericansHowever the prevalence for all Hispanic subgroups wassignificantly lower than the prevalence of 72 for non-Hispanic whites (Table 1)

Immigrant women in most racialethnic groups hadlower rates of maternal hypertension than their US-born

counterparts with the prevalence ranging from 19 forChinese immigrants and 23 for Japanese immigrants to103 for US-born blacks (Table 2) For example Chineseimmigrants had a 56 lower risk of maternal hypertensionthan US-born Chinese Vietnamese immigrants had a 44lower risk thanUS-born Vietnamese black immigrants had a31 lower risk thanUS-born blacksMexican immigrants hada 22 lower risk than US-born Mexicans and non-Hispanicwhite immigrants had a 45 lower risk than US-born non-Hispanic whites

Racialethnic groups varied greatly in their sociodemo-graphic and medical characteristics known to be associatedwith maternal hypertension (Table 3) For example whilelt13 of births occurred among AIAN Puerto Rican andblackmothers agedge35 years this percentagewas 32amongChinese and Filipinos 37 among Koreans and 49 amongJapanese mothers Educational attainment was the highestamong Asian Indian and Korean women and the lowestamong Mexican and Samoan women The percentage ofmothers with a college degree ranged from 767 for Koreansand 783 for Asian Indians to 74 for Samoans 91 forMexicans and 92 for AIANs More than 87 of Chineseand Asian Indian mothers were foreign-born comparedwith 66 of non-Hispanic whites and 150 of blacksThe prevalence of gestational diabetes was 133 for AsianIndians 119 for Filipinos 116 for Vietnamese 101 forSamoans 10 for AIANs and 95 for Chinese comparedwith 56 for blacks and 57 for non-Hispanic whitesSamoan women had the highest prevalence of prepregnancyobesity (644) followed by Hawaiians (372) AIANs(360) blacks (350) Puerto Ricans (299) and Mexi-cans (291) Chinese women had the lowest prepregnancyobesity prevalence (27) Samoans Hawaiians CubansPuerto Ricans non-Hispanic Whites Blacks and AIANswere significantly more likely to experience excess weightgain (gt40 pounds) during pregnancy compared to womenin all Asian subgroups Approximately 223 of AIANsand 149 of non-Hispanic whites reported having smokedbefore pregnancy compared with lt3 of Asian mothersRacialethnic patterns in smoking during pregnancy weresimilar

After controlling for covariates women in allracialethnic groups had significantly higher risks ofmaternalhypertension compared to Chinese women (Table 1 Model2) Compared with Chinese women non-Hispanic whitesAIANs non-Hispanic blacks and Filipinos had respectively19 20 24 and 29 times higher adjusted odds of maternalhypertension Compared with Chinese women MexicansCentral and South Americans Puerto Ricans and Cubanshad respectively 15 16 17 and 18 times higher adjustedodds of maternal hypertension Compared with Chineseimmigrants the adjusted odds of maternal hypertensionwere 21 times higher for US-born Chinese 26 times higherfor black immigrants 35 times higher for US-born blacks17 times higher for non-Hispanic whites 28 times higher forUS-born non-Hispanic whites 35 times higher for Filipinoimmigrants 34 times higher for US-born Filipinos 30times higher for US-born Japanese and 29 times higher forAIANs (Table 2 Model 2) Sociodemographic and medical

International Journal of Hypertension 7

Table3Ra

cialethnicv

ariatio

nin

selected

socialandmedicalris

kfactorsfor

materna

lhypertensionUnitedStates2014-2015

(119873=79

66573)

RaceEthnicity

MaternalA

gege

35Years

Percent

Maternal

Educationge16

Years

Percent

ForeignBo

rnPercent

Gestatio

nal

Diabetes

Percent

Pre-pregnancy

Overw

eight(BM

Ige2

5)Prevalence

()

Pre-pregnancy

Obesity(BMIge

30)

Prevalence

()

Weightg

ainin

pregnancy

(gt40lbs)

Prevalence

()

Smok

ingBe

fore

Pregnancy

Percent

Smok

ingin

Pregnancy

Percent

AllRa

ces

160

306

223

64

508

251

213

105

81

Non

-Hisp

anicWhite

163

396

66

57

473

231

240

149

116

Non

-Hisp

anicBlack

128

159

150

56

618

350

217

9069

American

IndianA

N100

9216

100

631

360

228

223

179

Chinese

316

675

875

95143

27

147

04

02

Japanese

494

665

725

62

163

48

7721

09

Filip

ino

319

531

727

119

363

117

160

23

12As

ianIndian

187

783

899

133

377

98130

03

02

Korean

365

767

787

79199

50

141

26

14Vietnamese

292

399

813

116

158

36

129

1006

Haw

aiian

145

181

44

83

650

372

248

147

123

Samoan

120

74296

101

876

644

312

9981

Mexican

145

91492

76593

291

155

24

15Pu

erto

Rican

120

154

132

67

568

299

223

101

68

Cuban

170

266

519

52

471

199

257

35

23

CentralSou

thAmerican

208

175

828

64

520

205

149

1206

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafilesA

N=AlaskaN

ative

8 International Journal of Hypertension

risk factors accounted for 63 of racialethnic disparitiesand 46 of ethnic-immigrant disparities in maternalhypertension based on comparison of the disparity indicesfor the unadjusted and adjusted prevalence estimates (datanot shown)

Table 1 shows variation in the prevalence and odds ofmaternal hypertension according to other sociodemographiccharacteristics Increasing maternal age unmarried statusUS-born status lower education nonmetropolitan residenceresidence in the Southern United States prepregnancy obe-sity excess weight gain during pregnancy and gestationaldiabetes were all associated with increased risks of maternalhypertensionWomen aged 40ndash44 andge45 years had respec-tively 17 and 25 times higher adjusted odds of maternalhypertension than those aged lt20 years Women with ges-tational diabetes had a 27 times higher prevalence and 24times higher adjusted odds of maternal hypertension thanthose who did not have gestational diabetes Compared towomen with normal weight (BMI lt 25) overweight womenas well as women with grade 1 and grade 2 obesity hadrespectively 17 27 and 46 times higher adjusted odds ofmaternal hypertension Women who gained gt40 pounds had94 higher adjusted odds of maternal hypertension thanthose who gained lt16 pounds during pregnancy Women inthe Southeastern and SouthwesternUnited States had 33ndash35higher adjusted odds of maternal hypertension than thoseliving in the Pacific region Although smoking during andbefore pregnancy was associated with 10 and 18 higherodds of maternal hypertension respectively after controllingfor sociodemographic and medical risk factors smoking wasfound to be not significantly related tomaternal hypertension(data not shown)

Racialethnic and ethnic-immigrant disparities in preg-nancy-related hypertension and chronic hypertension pre-sented in Tables 4 and 5 respectively generally show patternssimilar to those for the combined outcome ofmaternal hyper-tension However the effect-sizes for some risk factors suchas maternal age prepregnancy BMI smoking during andbefore pregnancy education and geographic residence werestronger for chronic hypertension than for pregnancy-relatedhypertension (data not shown for brevity) For examplecompared to those aged lt20 years women aged 40ndash44 andge45 years had respectively 88 and 120 times higher adjustedodds of chronic hypertension and 11 and 16 times higheradjusted odds of pregnancy-related hypertension Grade 1and grade 2 prepregnancy obesity were associated with 37and 78 times higher adjusted odds of chronic hypertensionand 25 and 37 times higher adjusted odds of pregnancy-related hypertension While maternal education was notsignificantly related to pregnancy-related hypertension aftercontrolling for other covariates there was a consistentand inverse educational gradient in chronic hypertensionWomen with less than a high school education had 30higher adjusted odds of chronic hypertension than those witha college degree Women in the Southeastern United Stateshad 87 higher adjusted odds and those in the New Englandregion had 62higher adjusted odds of chronic hypertensionthan those living in the Pacific region While smoking wasnot significantly related to pregnancy-related hypertension

smoking before and during pregnancy was associated with30ndash33higher risks of chronic hypertension Smoking beforeor during pregnancy was associated with 58-59 higher age-adjusted odds of chronic hypertension and 17-18 highercovariate-adjusted odds of chronic hypertension

Racialethnic variations in eclampsia were similar tothose for chronic andpregnancy-related hypertension Preva-lence of eclampsia was the highest among Samoan HawaiianNon-Hispanic black AIAN and Filipino women and thelowest among Chinese Vietnamese and Korean women(Figure 1) Compared with Chinese women blacks JapaneseSamoans Filipinos and Hawaiians had 3 to 4 times higheradjusted odds of eclampsia (data not shown) Immigrantwomen in most racialethnic groups had a lower risk ofeclampsia than their US-born counterparts The rate ofeclampsia ranged from 06 per 1000 live births for Chineseimmigrant women to 52 for Hawaiians and 53 per 1000 livebirths for Samoans (Figure 1) Chinese immigrants had 47lower adjusted odds than US-born Chinese Japanese immi-grants had 72 lower adjusted odds than US-born Japaneseblack immigrants had 17 lower adjusted odds thanUS-bornblacks and white immigrants had 19 lower adjusted odds ofeclampsia than US-born whites (data not shown) Maternalage lt 20 and ge45 years was associated with substantiallyincreased risks of eclampsia Women in the Southeast regionhad 23 times higher adjusted odds of eclampsia than those inthe Pacific region Gestational diabetes grade 1 prepregnancyobesity and grade 2 prepregnancy obesity were associatedwith 20 20 and 27 times higher adjusted odds of eclampsiarespectively (data not shown)

4 Discussion

To our knowledge this is the largest population-based studyof maternal hypertension in the United States The resultsof this national study indicate substantial racialethnic andnativity differences in the risk of maternal hypertensionwhich were only partially explained by differences in mater-nal age education prepregnancy BMI weight gain duringpregnancy gestational diabetes and other relevant sociode-mographic characteristics The detailed analysis of maternalhypertension prevalence among specific API and Hispanicsubgroups as well as among a large number of immigrantgroups is a particularly novel feature of our study Theincreased risks ofmaternal hypertension amongAIANs non-Hispanic whites blacks and Puerto Ricans are consistentwith those reported in previous US studies [6 8 10ndash12]Significantly higher risks of maternal hypertension amongFilipinos Samoans and Hawaiians and lower risks amongother Asian groups such as Chinese Japanese Koreans andVietnamese reported in our study are consistent with two USstudies conducted in Hawaii and New York City that showsimilar racialethnic patterns in maternal hypertension andpreeclampsia [8 13] Our findings of lower risks of maternalhypertension among Mexicans Cubans and CentralSouthAmericans are compatible with previous studies that showlower risks of hypertension among Hispanics compared tonon-Hispanic whites but higher risks amongHispanics whencompared to Asian groups [4 8 11 12]

International Journal of Hypertension 9

Table 4 Observed prevalence and adjusted odds of pregnancy-related hypertension among 17 racialethnic and 31 ethnic-immigrant groupsUnited States 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 567 322lowast 348 333 364 196 187 205Non-Hispanic Black 655 372lowast 408 390 426 205 196 215American IndianAlaska Native 677 385lowast 425 404 448 196 186 207Chinese 176 100 100 Reference 100 ReferenceJapanese 269 153lowast 147 132 165 150 134 168Filipino 587 334lowast 348 330 368 274 259 289Hawaiian 562 319lowast 346 281 427 167 135 207Asian Indian 326 185lowast 194 184 205 156 148 164Korean 277 157lowast 158 145 171 146 135 159Vietnamese 242 138lowast 138 128 150 131 122 142Samoan 681 387lowast 429 378 486 166 146 189Other AsianPacific Islander 350 199lowast 209 198 220 155 147 163Mexican 428 243lowast 259 248 271 156 149 163Puerto Rican 473 269lowast 290 276 305 167 158 175Cuban 477 271lowast 290 272 308 188 176 200Central amp South American 359 204lowast 213 203 223 164 156 172Other Hispanic 486 276lowast 297 284 311 172 164 180Ethnic-immigrant statusNon-Hispanic White US-born 584 382lowast 420 441 400 263 277 251Non-Hispanic White immigrant 330 216lowast 222 228 216 173 178 168Non-Hispanic Black US-born 683 446lowast 506 526 486 272 283 261Non-Hispanic Black immigrant 491 321lowast 335 344 326 234 241 228American IndianAlaska Native 677 442lowast 500 510 490 260 266 255Chinese US-born 337 220lowast 223 214 233 202 194 211Chinese immigrant 153 100 100 Reference 100 ReferenceJapanese US-born 475 310lowast 311 281 343 269 244 298Japanese immigrant 192 125lowast 118 107 130 133 122 146Hawaiian 562 367lowast 405 346 473 220 188 258Filipino US-born 609 398lowast 428 421 434 308 304 313Filipino immigrant 579 378lowast 393 396 390 324 328 322Asian Indian US-born 374 244lowast 255 244 265 199 191 207Asian Indian immigrant 320 209lowast 221 225 218 173 176 171Korean US-born 291 190lowast 195 176 215 172 156 190Korean immigrant 275 180lowast 179 173 184 170 165 175Vietnamese US-born 377 246lowast 266 248 285 213 199 229Vietnamese immigrant 210 137lowast 137 133 141 136 132 139Samoan 681 445lowast 503 468 539 209 195 224Other AsianPacific Islander US-born 405 265lowast 287 288 286 196 197 195Other AsianPacific Islander immigrant 318 208lowast 217 219 215 178 180 176Mexican US-born 482 315lowast 350 363 338 200 207 193Mexican immigrant 372 243lowast 258 266 249 181 188 175Puerto Rican mainland US-born 469 307lowast 338 345 330 216 220 211Puerto Rican Puerto Rico-born 509 333lowast 363 357 370 228 225 233Cuban US-born 492 322lowast 351 345 357 221 218 225Cuban immigrant 464 303lowast 326 321 331 239 236 243Central amp South American US-born 422 276lowast 302 302 300 195 196 194Central amp South American immigrant 346 226lowast 237 243 231 188 193 183Other Hispanic US-born 499 326lowast 363 373 352 213 220 208Other Hispanic immigrant 455 297lowast 317 322 312 235 239 232All other ethnic-nativity groups 523 342lowast 371 364 377 265 261 270OR = odds ratio CI = confidence interval lowastStatistically significant at 119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that forthe reference group 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region ofresidence gestational diabetes prepregnancy BMI and gestational weight gain Source Data derived from the 2014-2015 US National Natality data files

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

International Journal of Hypertension 7

Table3Ra

cialethnicv

ariatio

nin

selected

socialandmedicalris

kfactorsfor

materna

lhypertensionUnitedStates2014-2015

(119873=79

66573)

RaceEthnicity

MaternalA

gege

35Years

Percent

Maternal

Educationge16

Years

Percent

ForeignBo

rnPercent

Gestatio

nal

Diabetes

Percent

Pre-pregnancy

Overw

eight(BM

Ige2

5)Prevalence

()

Pre-pregnancy

Obesity(BMIge

30)

Prevalence

()

Weightg

ainin

pregnancy

(gt40lbs)

Prevalence

()

Smok

ingBe

fore

Pregnancy

Percent

Smok

ingin

Pregnancy

Percent

AllRa

ces

160

306

223

64

508

251

213

105

81

Non

-Hisp

anicWhite

163

396

66

57

473

231

240

149

116

Non

-Hisp

anicBlack

128

159

150

56

618

350

217

9069

American

IndianA

N100

9216

100

631

360

228

223

179

Chinese

316

675

875

95143

27

147

04

02

Japanese

494

665

725

62

163

48

7721

09

Filip

ino

319

531

727

119

363

117

160

23

12As

ianIndian

187

783

899

133

377

98130

03

02

Korean

365

767

787

79199

50

141

26

14Vietnamese

292

399

813

116

158

36

129

1006

Haw

aiian

145

181

44

83

650

372

248

147

123

Samoan

120

74296

101

876

644

312

9981

Mexican

145

91492

76593

291

155

24

15Pu

erto

Rican

120

154

132

67

568

299

223

101

68

Cuban

170

266

519

52

471

199

257

35

23

CentralSou

thAmerican

208

175

828

64

520

205

149

1206

SourceD

atad

erived

from

the2

014-2015

USNationalN

atality

datafilesA

N=AlaskaN

ative

8 International Journal of Hypertension

risk factors accounted for 63 of racialethnic disparitiesand 46 of ethnic-immigrant disparities in maternalhypertension based on comparison of the disparity indicesfor the unadjusted and adjusted prevalence estimates (datanot shown)

Table 1 shows variation in the prevalence and odds ofmaternal hypertension according to other sociodemographiccharacteristics Increasing maternal age unmarried statusUS-born status lower education nonmetropolitan residenceresidence in the Southern United States prepregnancy obe-sity excess weight gain during pregnancy and gestationaldiabetes were all associated with increased risks of maternalhypertensionWomen aged 40ndash44 andge45 years had respec-tively 17 and 25 times higher adjusted odds of maternalhypertension than those aged lt20 years Women with ges-tational diabetes had a 27 times higher prevalence and 24times higher adjusted odds of maternal hypertension thanthose who did not have gestational diabetes Compared towomen with normal weight (BMI lt 25) overweight womenas well as women with grade 1 and grade 2 obesity hadrespectively 17 27 and 46 times higher adjusted odds ofmaternal hypertension Women who gained gt40 pounds had94 higher adjusted odds of maternal hypertension thanthose who gained lt16 pounds during pregnancy Women inthe Southeastern and SouthwesternUnited States had 33ndash35higher adjusted odds of maternal hypertension than thoseliving in the Pacific region Although smoking during andbefore pregnancy was associated with 10 and 18 higherodds of maternal hypertension respectively after controllingfor sociodemographic and medical risk factors smoking wasfound to be not significantly related tomaternal hypertension(data not shown)

Racialethnic and ethnic-immigrant disparities in preg-nancy-related hypertension and chronic hypertension pre-sented in Tables 4 and 5 respectively generally show patternssimilar to those for the combined outcome ofmaternal hyper-tension However the effect-sizes for some risk factors suchas maternal age prepregnancy BMI smoking during andbefore pregnancy education and geographic residence werestronger for chronic hypertension than for pregnancy-relatedhypertension (data not shown for brevity) For examplecompared to those aged lt20 years women aged 40ndash44 andge45 years had respectively 88 and 120 times higher adjustedodds of chronic hypertension and 11 and 16 times higheradjusted odds of pregnancy-related hypertension Grade 1and grade 2 prepregnancy obesity were associated with 37and 78 times higher adjusted odds of chronic hypertensionand 25 and 37 times higher adjusted odds of pregnancy-related hypertension While maternal education was notsignificantly related to pregnancy-related hypertension aftercontrolling for other covariates there was a consistentand inverse educational gradient in chronic hypertensionWomen with less than a high school education had 30higher adjusted odds of chronic hypertension than those witha college degree Women in the Southeastern United Stateshad 87 higher adjusted odds and those in the New Englandregion had 62higher adjusted odds of chronic hypertensionthan those living in the Pacific region While smoking wasnot significantly related to pregnancy-related hypertension

smoking before and during pregnancy was associated with30ndash33higher risks of chronic hypertension Smoking beforeor during pregnancy was associated with 58-59 higher age-adjusted odds of chronic hypertension and 17-18 highercovariate-adjusted odds of chronic hypertension

Racialethnic variations in eclampsia were similar tothose for chronic andpregnancy-related hypertension Preva-lence of eclampsia was the highest among Samoan HawaiianNon-Hispanic black AIAN and Filipino women and thelowest among Chinese Vietnamese and Korean women(Figure 1) Compared with Chinese women blacks JapaneseSamoans Filipinos and Hawaiians had 3 to 4 times higheradjusted odds of eclampsia (data not shown) Immigrantwomen in most racialethnic groups had a lower risk ofeclampsia than their US-born counterparts The rate ofeclampsia ranged from 06 per 1000 live births for Chineseimmigrant women to 52 for Hawaiians and 53 per 1000 livebirths for Samoans (Figure 1) Chinese immigrants had 47lower adjusted odds than US-born Chinese Japanese immi-grants had 72 lower adjusted odds than US-born Japaneseblack immigrants had 17 lower adjusted odds thanUS-bornblacks and white immigrants had 19 lower adjusted odds ofeclampsia than US-born whites (data not shown) Maternalage lt 20 and ge45 years was associated with substantiallyincreased risks of eclampsia Women in the Southeast regionhad 23 times higher adjusted odds of eclampsia than those inthe Pacific region Gestational diabetes grade 1 prepregnancyobesity and grade 2 prepregnancy obesity were associatedwith 20 20 and 27 times higher adjusted odds of eclampsiarespectively (data not shown)

4 Discussion

To our knowledge this is the largest population-based studyof maternal hypertension in the United States The resultsof this national study indicate substantial racialethnic andnativity differences in the risk of maternal hypertensionwhich were only partially explained by differences in mater-nal age education prepregnancy BMI weight gain duringpregnancy gestational diabetes and other relevant sociode-mographic characteristics The detailed analysis of maternalhypertension prevalence among specific API and Hispanicsubgroups as well as among a large number of immigrantgroups is a particularly novel feature of our study Theincreased risks ofmaternal hypertension amongAIANs non-Hispanic whites blacks and Puerto Ricans are consistentwith those reported in previous US studies [6 8 10ndash12]Significantly higher risks of maternal hypertension amongFilipinos Samoans and Hawaiians and lower risks amongother Asian groups such as Chinese Japanese Koreans andVietnamese reported in our study are consistent with two USstudies conducted in Hawaii and New York City that showsimilar racialethnic patterns in maternal hypertension andpreeclampsia [8 13] Our findings of lower risks of maternalhypertension among Mexicans Cubans and CentralSouthAmericans are compatible with previous studies that showlower risks of hypertension among Hispanics compared tonon-Hispanic whites but higher risks amongHispanics whencompared to Asian groups [4 8 11 12]

International Journal of Hypertension 9

Table 4 Observed prevalence and adjusted odds of pregnancy-related hypertension among 17 racialethnic and 31 ethnic-immigrant groupsUnited States 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 567 322lowast 348 333 364 196 187 205Non-Hispanic Black 655 372lowast 408 390 426 205 196 215American IndianAlaska Native 677 385lowast 425 404 448 196 186 207Chinese 176 100 100 Reference 100 ReferenceJapanese 269 153lowast 147 132 165 150 134 168Filipino 587 334lowast 348 330 368 274 259 289Hawaiian 562 319lowast 346 281 427 167 135 207Asian Indian 326 185lowast 194 184 205 156 148 164Korean 277 157lowast 158 145 171 146 135 159Vietnamese 242 138lowast 138 128 150 131 122 142Samoan 681 387lowast 429 378 486 166 146 189Other AsianPacific Islander 350 199lowast 209 198 220 155 147 163Mexican 428 243lowast 259 248 271 156 149 163Puerto Rican 473 269lowast 290 276 305 167 158 175Cuban 477 271lowast 290 272 308 188 176 200Central amp South American 359 204lowast 213 203 223 164 156 172Other Hispanic 486 276lowast 297 284 311 172 164 180Ethnic-immigrant statusNon-Hispanic White US-born 584 382lowast 420 441 400 263 277 251Non-Hispanic White immigrant 330 216lowast 222 228 216 173 178 168Non-Hispanic Black US-born 683 446lowast 506 526 486 272 283 261Non-Hispanic Black immigrant 491 321lowast 335 344 326 234 241 228American IndianAlaska Native 677 442lowast 500 510 490 260 266 255Chinese US-born 337 220lowast 223 214 233 202 194 211Chinese immigrant 153 100 100 Reference 100 ReferenceJapanese US-born 475 310lowast 311 281 343 269 244 298Japanese immigrant 192 125lowast 118 107 130 133 122 146Hawaiian 562 367lowast 405 346 473 220 188 258Filipino US-born 609 398lowast 428 421 434 308 304 313Filipino immigrant 579 378lowast 393 396 390 324 328 322Asian Indian US-born 374 244lowast 255 244 265 199 191 207Asian Indian immigrant 320 209lowast 221 225 218 173 176 171Korean US-born 291 190lowast 195 176 215 172 156 190Korean immigrant 275 180lowast 179 173 184 170 165 175Vietnamese US-born 377 246lowast 266 248 285 213 199 229Vietnamese immigrant 210 137lowast 137 133 141 136 132 139Samoan 681 445lowast 503 468 539 209 195 224Other AsianPacific Islander US-born 405 265lowast 287 288 286 196 197 195Other AsianPacific Islander immigrant 318 208lowast 217 219 215 178 180 176Mexican US-born 482 315lowast 350 363 338 200 207 193Mexican immigrant 372 243lowast 258 266 249 181 188 175Puerto Rican mainland US-born 469 307lowast 338 345 330 216 220 211Puerto Rican Puerto Rico-born 509 333lowast 363 357 370 228 225 233Cuban US-born 492 322lowast 351 345 357 221 218 225Cuban immigrant 464 303lowast 326 321 331 239 236 243Central amp South American US-born 422 276lowast 302 302 300 195 196 194Central amp South American immigrant 346 226lowast 237 243 231 188 193 183Other Hispanic US-born 499 326lowast 363 373 352 213 220 208Other Hispanic immigrant 455 297lowast 317 322 312 235 239 232All other ethnic-nativity groups 523 342lowast 371 364 377 265 261 270OR = odds ratio CI = confidence interval lowastStatistically significant at 119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that forthe reference group 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region ofresidence gestational diabetes prepregnancy BMI and gestational weight gain Source Data derived from the 2014-2015 US National Natality data files

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

8 International Journal of Hypertension

risk factors accounted for 63 of racialethnic disparitiesand 46 of ethnic-immigrant disparities in maternalhypertension based on comparison of the disparity indicesfor the unadjusted and adjusted prevalence estimates (datanot shown)

Table 1 shows variation in the prevalence and odds ofmaternal hypertension according to other sociodemographiccharacteristics Increasing maternal age unmarried statusUS-born status lower education nonmetropolitan residenceresidence in the Southern United States prepregnancy obe-sity excess weight gain during pregnancy and gestationaldiabetes were all associated with increased risks of maternalhypertensionWomen aged 40ndash44 andge45 years had respec-tively 17 and 25 times higher adjusted odds of maternalhypertension than those aged lt20 years Women with ges-tational diabetes had a 27 times higher prevalence and 24times higher adjusted odds of maternal hypertension thanthose who did not have gestational diabetes Compared towomen with normal weight (BMI lt 25) overweight womenas well as women with grade 1 and grade 2 obesity hadrespectively 17 27 and 46 times higher adjusted odds ofmaternal hypertension Women who gained gt40 pounds had94 higher adjusted odds of maternal hypertension thanthose who gained lt16 pounds during pregnancy Women inthe Southeastern and SouthwesternUnited States had 33ndash35higher adjusted odds of maternal hypertension than thoseliving in the Pacific region Although smoking during andbefore pregnancy was associated with 10 and 18 higherodds of maternal hypertension respectively after controllingfor sociodemographic and medical risk factors smoking wasfound to be not significantly related tomaternal hypertension(data not shown)

Racialethnic and ethnic-immigrant disparities in preg-nancy-related hypertension and chronic hypertension pre-sented in Tables 4 and 5 respectively generally show patternssimilar to those for the combined outcome ofmaternal hyper-tension However the effect-sizes for some risk factors suchas maternal age prepregnancy BMI smoking during andbefore pregnancy education and geographic residence werestronger for chronic hypertension than for pregnancy-relatedhypertension (data not shown for brevity) For examplecompared to those aged lt20 years women aged 40ndash44 andge45 years had respectively 88 and 120 times higher adjustedodds of chronic hypertension and 11 and 16 times higheradjusted odds of pregnancy-related hypertension Grade 1and grade 2 prepregnancy obesity were associated with 37and 78 times higher adjusted odds of chronic hypertensionand 25 and 37 times higher adjusted odds of pregnancy-related hypertension While maternal education was notsignificantly related to pregnancy-related hypertension aftercontrolling for other covariates there was a consistentand inverse educational gradient in chronic hypertensionWomen with less than a high school education had 30higher adjusted odds of chronic hypertension than those witha college degree Women in the Southeastern United Stateshad 87 higher adjusted odds and those in the New Englandregion had 62higher adjusted odds of chronic hypertensionthan those living in the Pacific region While smoking wasnot significantly related to pregnancy-related hypertension

smoking before and during pregnancy was associated with30ndash33higher risks of chronic hypertension Smoking beforeor during pregnancy was associated with 58-59 higher age-adjusted odds of chronic hypertension and 17-18 highercovariate-adjusted odds of chronic hypertension

Racialethnic variations in eclampsia were similar tothose for chronic andpregnancy-related hypertension Preva-lence of eclampsia was the highest among Samoan HawaiianNon-Hispanic black AIAN and Filipino women and thelowest among Chinese Vietnamese and Korean women(Figure 1) Compared with Chinese women blacks JapaneseSamoans Filipinos and Hawaiians had 3 to 4 times higheradjusted odds of eclampsia (data not shown) Immigrantwomen in most racialethnic groups had a lower risk ofeclampsia than their US-born counterparts The rate ofeclampsia ranged from 06 per 1000 live births for Chineseimmigrant women to 52 for Hawaiians and 53 per 1000 livebirths for Samoans (Figure 1) Chinese immigrants had 47lower adjusted odds than US-born Chinese Japanese immi-grants had 72 lower adjusted odds than US-born Japaneseblack immigrants had 17 lower adjusted odds thanUS-bornblacks and white immigrants had 19 lower adjusted odds ofeclampsia than US-born whites (data not shown) Maternalage lt 20 and ge45 years was associated with substantiallyincreased risks of eclampsia Women in the Southeast regionhad 23 times higher adjusted odds of eclampsia than those inthe Pacific region Gestational diabetes grade 1 prepregnancyobesity and grade 2 prepregnancy obesity were associatedwith 20 20 and 27 times higher adjusted odds of eclampsiarespectively (data not shown)

4 Discussion

To our knowledge this is the largest population-based studyof maternal hypertension in the United States The resultsof this national study indicate substantial racialethnic andnativity differences in the risk of maternal hypertensionwhich were only partially explained by differences in mater-nal age education prepregnancy BMI weight gain duringpregnancy gestational diabetes and other relevant sociode-mographic characteristics The detailed analysis of maternalhypertension prevalence among specific API and Hispanicsubgroups as well as among a large number of immigrantgroups is a particularly novel feature of our study Theincreased risks ofmaternal hypertension amongAIANs non-Hispanic whites blacks and Puerto Ricans are consistentwith those reported in previous US studies [6 8 10ndash12]Significantly higher risks of maternal hypertension amongFilipinos Samoans and Hawaiians and lower risks amongother Asian groups such as Chinese Japanese Koreans andVietnamese reported in our study are consistent with two USstudies conducted in Hawaii and New York City that showsimilar racialethnic patterns in maternal hypertension andpreeclampsia [8 13] Our findings of lower risks of maternalhypertension among Mexicans Cubans and CentralSouthAmericans are compatible with previous studies that showlower risks of hypertension among Hispanics compared tonon-Hispanic whites but higher risks amongHispanics whencompared to Asian groups [4 8 11 12]

International Journal of Hypertension 9

Table 4 Observed prevalence and adjusted odds of pregnancy-related hypertension among 17 racialethnic and 31 ethnic-immigrant groupsUnited States 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 567 322lowast 348 333 364 196 187 205Non-Hispanic Black 655 372lowast 408 390 426 205 196 215American IndianAlaska Native 677 385lowast 425 404 448 196 186 207Chinese 176 100 100 Reference 100 ReferenceJapanese 269 153lowast 147 132 165 150 134 168Filipino 587 334lowast 348 330 368 274 259 289Hawaiian 562 319lowast 346 281 427 167 135 207Asian Indian 326 185lowast 194 184 205 156 148 164Korean 277 157lowast 158 145 171 146 135 159Vietnamese 242 138lowast 138 128 150 131 122 142Samoan 681 387lowast 429 378 486 166 146 189Other AsianPacific Islander 350 199lowast 209 198 220 155 147 163Mexican 428 243lowast 259 248 271 156 149 163Puerto Rican 473 269lowast 290 276 305 167 158 175Cuban 477 271lowast 290 272 308 188 176 200Central amp South American 359 204lowast 213 203 223 164 156 172Other Hispanic 486 276lowast 297 284 311 172 164 180Ethnic-immigrant statusNon-Hispanic White US-born 584 382lowast 420 441 400 263 277 251Non-Hispanic White immigrant 330 216lowast 222 228 216 173 178 168Non-Hispanic Black US-born 683 446lowast 506 526 486 272 283 261Non-Hispanic Black immigrant 491 321lowast 335 344 326 234 241 228American IndianAlaska Native 677 442lowast 500 510 490 260 266 255Chinese US-born 337 220lowast 223 214 233 202 194 211Chinese immigrant 153 100 100 Reference 100 ReferenceJapanese US-born 475 310lowast 311 281 343 269 244 298Japanese immigrant 192 125lowast 118 107 130 133 122 146Hawaiian 562 367lowast 405 346 473 220 188 258Filipino US-born 609 398lowast 428 421 434 308 304 313Filipino immigrant 579 378lowast 393 396 390 324 328 322Asian Indian US-born 374 244lowast 255 244 265 199 191 207Asian Indian immigrant 320 209lowast 221 225 218 173 176 171Korean US-born 291 190lowast 195 176 215 172 156 190Korean immigrant 275 180lowast 179 173 184 170 165 175Vietnamese US-born 377 246lowast 266 248 285 213 199 229Vietnamese immigrant 210 137lowast 137 133 141 136 132 139Samoan 681 445lowast 503 468 539 209 195 224Other AsianPacific Islander US-born 405 265lowast 287 288 286 196 197 195Other AsianPacific Islander immigrant 318 208lowast 217 219 215 178 180 176Mexican US-born 482 315lowast 350 363 338 200 207 193Mexican immigrant 372 243lowast 258 266 249 181 188 175Puerto Rican mainland US-born 469 307lowast 338 345 330 216 220 211Puerto Rican Puerto Rico-born 509 333lowast 363 357 370 228 225 233Cuban US-born 492 322lowast 351 345 357 221 218 225Cuban immigrant 464 303lowast 326 321 331 239 236 243Central amp South American US-born 422 276lowast 302 302 300 195 196 194Central amp South American immigrant 346 226lowast 237 243 231 188 193 183Other Hispanic US-born 499 326lowast 363 373 352 213 220 208Other Hispanic immigrant 455 297lowast 317 322 312 235 239 232All other ethnic-nativity groups 523 342lowast 371 364 377 265 261 270OR = odds ratio CI = confidence interval lowastStatistically significant at 119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that forthe reference group 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region ofresidence gestational diabetes prepregnancy BMI and gestational weight gain Source Data derived from the 2014-2015 US National Natality data files

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

International Journal of Hypertension 9

Table 4 Observed prevalence and adjusted odds of pregnancy-related hypertension among 17 racialethnic and 31 ethnic-immigrant groupsUnited States 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 567 322lowast 348 333 364 196 187 205Non-Hispanic Black 655 372lowast 408 390 426 205 196 215American IndianAlaska Native 677 385lowast 425 404 448 196 186 207Chinese 176 100 100 Reference 100 ReferenceJapanese 269 153lowast 147 132 165 150 134 168Filipino 587 334lowast 348 330 368 274 259 289Hawaiian 562 319lowast 346 281 427 167 135 207Asian Indian 326 185lowast 194 184 205 156 148 164Korean 277 157lowast 158 145 171 146 135 159Vietnamese 242 138lowast 138 128 150 131 122 142Samoan 681 387lowast 429 378 486 166 146 189Other AsianPacific Islander 350 199lowast 209 198 220 155 147 163Mexican 428 243lowast 259 248 271 156 149 163Puerto Rican 473 269lowast 290 276 305 167 158 175Cuban 477 271lowast 290 272 308 188 176 200Central amp South American 359 204lowast 213 203 223 164 156 172Other Hispanic 486 276lowast 297 284 311 172 164 180Ethnic-immigrant statusNon-Hispanic White US-born 584 382lowast 420 441 400 263 277 251Non-Hispanic White immigrant 330 216lowast 222 228 216 173 178 168Non-Hispanic Black US-born 683 446lowast 506 526 486 272 283 261Non-Hispanic Black immigrant 491 321lowast 335 344 326 234 241 228American IndianAlaska Native 677 442lowast 500 510 490 260 266 255Chinese US-born 337 220lowast 223 214 233 202 194 211Chinese immigrant 153 100 100 Reference 100 ReferenceJapanese US-born 475 310lowast 311 281 343 269 244 298Japanese immigrant 192 125lowast 118 107 130 133 122 146Hawaiian 562 367lowast 405 346 473 220 188 258Filipino US-born 609 398lowast 428 421 434 308 304 313Filipino immigrant 579 378lowast 393 396 390 324 328 322Asian Indian US-born 374 244lowast 255 244 265 199 191 207Asian Indian immigrant 320 209lowast 221 225 218 173 176 171Korean US-born 291 190lowast 195 176 215 172 156 190Korean immigrant 275 180lowast 179 173 184 170 165 175Vietnamese US-born 377 246lowast 266 248 285 213 199 229Vietnamese immigrant 210 137lowast 137 133 141 136 132 139Samoan 681 445lowast 503 468 539 209 195 224Other AsianPacific Islander US-born 405 265lowast 287 288 286 196 197 195Other AsianPacific Islander immigrant 318 208lowast 217 219 215 178 180 176Mexican US-born 482 315lowast 350 363 338 200 207 193Mexican immigrant 372 243lowast 258 266 249 181 188 175Puerto Rican mainland US-born 469 307lowast 338 345 330 216 220 211Puerto Rican Puerto Rico-born 509 333lowast 363 357 370 228 225 233Cuban US-born 492 322lowast 351 345 357 221 218 225Cuban immigrant 464 303lowast 326 321 331 239 236 243Central amp South American US-born 422 276lowast 302 302 300 195 196 194Central amp South American immigrant 346 226lowast 237 243 231 188 193 183Other Hispanic US-born 499 326lowast 363 373 352 213 220 208Other Hispanic immigrant 455 297lowast 317 322 312 235 239 232All other ethnic-nativity groups 523 342lowast 371 364 377 265 261 270OR = odds ratio CI = confidence interval lowastStatistically significant at 119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that forthe reference group 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region ofresidence gestational diabetes prepregnancy BMI and gestational weight gain Source Data derived from the 2014-2015 US National Natality data files

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

10 International Journal of Hypertension

Table 5 Observed prevalence and adjusted odds of chronic hypertension among 17 racialethnic and 31 ethnic-immigrant groups UnitedStates 2014-2015 (119873 = 7966573)

Ethnicity and immigrant status Prevalence percent Prevalence ratio1 Model 12 Model 23

OR 95 CI OR 95 CIRaceethnicityNon-Hispanic White 150 375lowast 487 444 533 159 145 175Non-Hispanic Black 327 818lowast 1247 1138 1367 298 271 327American IndianAlaska Native 216 540lowast 860 775 954 204 184 227Chinese 040 100 100 Reference 100 ReferenceJapanese 075 188lowast 161 130 198 147 119 182Filipino 186 465lowast 484 434 539 343 308 382Hawaiian 133 333lowast 453 297 691 124 081 189Asian Indian 072 180lowast 205 184 230 151 135 169Korean 083 208lowast 195 168 228 174 149 203Vietnamese 051 128lowast 131 112 155 119 101 140Samoan 178 445lowast 655 513 836 148 116 189Other AsianPacific Islander 094 235lowast 288 259 320 149 134 166Mexican 089 223lowast 315 287 346 111 101 122Puerto Rican 162 405lowast 615 557 680 167 150 185Cuban 109 273lowast 349 307 398 140 123 160Central amp South American 095 238lowast 295 267 325 133 121 147Other Hispanic 114 285lowast 427 387 470 140 127 154Ethnic-immigrant statusNon-Hispanic White US-born 155 470lowast 255 273 239 154 165 144Non-Hispanic White immigrant 078 236lowast 621 694 559 272 304 244Non-Hispanic Black US-born 347 1052lowast 1753 1934 1598 514 564 468Non-Hispanic Black immigrant 217 658lowast 710 768 660 301 325 279American IndianAlaska Native 216 655lowast 1060 1127 1002 346 366 326Chinese US-born 088 267lowast 257 241 274 235 220 252Chinese immigrant 033 100 100 Reference 100 ReferenceJapanese US-born 170 515lowast 462 405 530 405 353 465Japanese immigrant 040 121 098 081 120 101 082 123Hawaiian 133 403lowast 553 409 751 206 152 280Filipino US-born 190 576lowast 648 649 650 424 423 425Filipino immigrant 184 558lowast 553 577 532 437 454 420Asian Indian US-born 078 236lowast 247 228 269 172 158 188Asian Indian immigrant 071 215lowast 248 259 239 177 184 170Korean US-born 091 276lowast 275 237 321 244 209 284Korean immigrant 081 245lowast 223 216 232 208 201 216Vietnamese US-born 078 236lowast 292 253 339 230 198 266Vietnamese immigrant 045 136lowast 133 127 141 125 119 132Samoan 178 539lowast 804 717 906 223 198 251Other AsianPacific Islander US-born 106 321lowast 439 450 429 236 241 230Other AsianPacific Islander immigrant 087 264lowast 301 314 292 173 179 167Mexican US-born 098 297lowast 502 546 464 189 205 175Mexican immigrant 079 239lowast 297 322 275 123 133 114Puerto Rican mainland US-born 157 476lowast 740 790 697 263 280 248Puerto Rican Puerto Rico-born 195 591lowast 846 851 845 306 307 306Cuban US-born 123 373lowast 498 491 509 217 213 221Cuban immigrant 095 288lowast 360 351 372 178 173 183Central amp South American US-born 108 327lowast 501 513 491 216 221 212Central amp South American immigrant 093 282lowast 334 357 313 150 160 141Other Hispanic US-born 106 321lowast 532 569 500 205 218 192Other Hispanic immigrant 136 412lowast 506 533 483 223 234 213All other ethnic-nativity groups 168 509lowast 674 672 679 304 303 306OR=odds ratio CI = confidence interval lowastStatistically significant at119901 lt 005 1Defined as the ratio of the prevalence for a specific group to that for the referencegroup 2Adjusted for maternal age only 3Adjusted for maternal age marital status nativity plurality maternal education place and region of residence andprepregnancy BMI Source Data derived from the 2014-2015 US National Natality data files

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

International Journal of Hypertension 11

007

009

011

014

014

016

017

018

019

020

020

022

023

023

024

034

037

040

052

053

Chinese

Source Data derived from the 2014-2015 US National Natality Files

Vietnamese

Korean

Asian Indian

Cuban

Mexican

All AsianPacificIslanders

All Hispanics

Central amp SouthAmerican

Other AsianPacificIslander

Other Hispanic

Puerto Rican

Non-Hispanic White

Japanese

Total US population

Filipino

American IndianAlaska Native

Non-Hispanic Black

Hawaiian

Samoan

Racialethnic variation in eclampsia

006

007

009

011

012

013

013

014

014

015

016

016

017

017

017

018

019

020

022

023

024

026

028

030

033

037

037

042

049

052

053

Chinese immigrant

Vietnamese immigrant

Korean immigrant

Cuban immigrant

Chinese US-born

Japanese immigrant

Asian Indian US-born

Asian Indian immigrant

Other AsianPacific Islander immigrant

Non-Hispanic White immigrant

Mexican US-born

Central amp South American US-born

Vietnamese US-born

Mexican immigrant

Cuban US-born

Other Hispanic US-born

Korean US-born

Central amp South American immigrant

Puerto Rican mainland US-born

Puerto Rican Puerto Rico-born

Non-Hispanic White US-born

Other Hispanic immigrant

Non-Hispanic Black immigrant

Other AsianPacific Islander US-born

Filipino immigrant

American IndianAlaska Native

Filipino US-born

Non-Hispanic Black US-born

Japanese US-born

Hawaiian

Samoan

Ethnic-immigrant variation in eclampsia

Figure 1 Prevalence () of eclampsia among women in 17 racialethnic and 31 ethnic-immigrant groups United States 2014-2015

Racialethnic patterns in maternal hypertension docu-mented here are largely consistent with those observed inhypertension among the adult population and for repro-ductive age women in the US [25 26] Data from the2010ndash2014 US National Health Interview Survey show thatnon-Hispanic black women aged 18ndash49 had the highestprevalence of hypertension (223) followed by NativeHawaiiansPacific Islanders (200) AIANs (160) Fil-ipinos (128) and non-Hispanic whites (122) ChineseAsian Indians and other Asians including Japanese KoreanandVietnamesewomen aged 18ndash49 had the lowest prevalence(lt7) [26]

Besides raceethnicity and immigrant status the otherimportant predictors of maternal hypertension includedmaternal age gestational diabetes prepregnancy BMI andgestational weight gain which are consistent with previousstudies [7 8 12 13]Thefinding of higher prevalence ofmater-nal hypertension in theMidwest and Southern regions is con-sistent with the previously reported regional patterns in adulthypertension [25] Increased risk of maternal hypertensionand chronic hypertension associated with lower educationis in line with the previously reported positive relationshipbetween low socioeconomic status (SES) and gestationalhypertension [8 27 28] The finding that immigrants in

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

12 International Journal of Hypertension

most racialethnic groups have a lower risk of maternalhypertension than their US-born counterparts is consistentwith studies that show significantly lower rates of maternalhypertension and adult hypertension among immigrants [1113 29]

Although immigrants account for 135 of the totalUS population immigrant women make up 204 of thereproductive-age population [14] Given the marked inequal-ities in maternal hypertension by immigrant status themagnitude of health disparities is likely to be substantial forwomen in reproductive ages [11 17] Although immigrantwomen in most racialethnic groups had lower rates ofmaternal hypertension than the US-born their reduced risksof hypertension and other health advantages are likely todiminish with increasing acculturation levels or duration ofresidence in the US [11 17] Although genetic factors mightpartly explain racialethnic disparities in maternal hyper-tension lower risks among immigrants relative to native-born women of similar ethnicities indicate the significanceof social environments acculturation and lifestyle factors[11 17] Ethnic-minority and socially disadvantaged groups intheUSdiffer greatly from themajority affluent groups in theirsocial physical and living environments thatmight influencehypertension and related risks such as prepregnancy obesitygestational diabetes and weight gain during pregnancyThey have limited access to neighborhood amenities suchas sidewalks parksplaygrounds green spaces public trans-portation and healthy affordable foods that promote physicalactivity healthy lifestyle and healthy living [11 21 22 30]

Our study has limitations Because of lack of data otherimportant risk factors for maternal hypertension such asdiet physical activity family history of hypertension andthe social and built environments which could explain someof the reported racialethnic and nativity differences couldnot be taken into account Socioeconomic data in our studywere also limited with maternal education being the onlySES measure available Other measures of SES such as familyincome occupation and neighborhood deprivation whichhave been associated with gestational hypertension and adulthypertension were lacking in our database [7 15 31] More-over because of the nature and quality of the birth certificatedata we could not fully distinguish between different hyper-tensive disorders of pregnancy such as chronic hyperten-sion preeclampsia eclampsia preeclampsia superimposedon chronic hypertension and gestational hypertension [15]Some of the women who did not receive timely and regularprenatal care in our study might have been missed frombeing screened for gestational hypertension Studies havefound underreporting of hypertensive disorders includingchronic hypertension pregnancy-induced hypertension andpreeclampsia on birth certificates when compared with hos-pital discharge data [32ndash34] Underreporting of hypertensionis found across all racialethnic and socioeconomic groups[32] However the degree of underreporting is noted to behigher among women with lower education and incomelevels which may have affected the socioeconomic gradientsin the overall outcome of maternal hypertension and specifichypertensive disorders shown here [32] The major strengthof our national study is its large sample size of 8 million

women which allowed us to compare risks of maternalhypertension and related risk factors among a large numberof racialethnic and immigrant groups Such subgroup com-parisons were not feasible in previously smaller studies

5 Conclusions

This large population-based study of 8 million US womenhas shown considerable heterogeneity in maternal hyperten-sion prevalence across various racialethnic and immigrantgroups Non-Hispanic whites and several ethnic-minoritygroups such as non-Hispanic blacks AIANs SamoansHawaiians Filipinos and Puerto Ricans have relatively highlevels of maternal hypertension exceeding 6 Most Asiangroups including Chinese Japanese Vietnamese Koreansand Asian Indians have substantially lower prevalence ofmaternal hypertension (lt4) High rates of maternal hyper-tension correspond closely with the higher prevalence ofimportant risk factors and perinatal outcomes among thesegroups such as prepregnancy obesity excess weight gainduring pregnancy smoking before and during pregnancylowermaternal education pregnancy complications pretermbirth and neonatal mortality [4 9ndash11] Formost racialethnicgroups immigrants have substantially lower rates of mater-nal hypertension than their US-born counterparts Thesefindings highlight the significance of stratifying analyses byimmigrant status and suggest ethnic-specific and culturallyappropriate interventions to prevent and control hyperten-sion and related risks such as prepregnancy obesity amongwomen of reproductive age and to improve health outcomes[11 17] Tackling the rising prevalence of chronic hyperten-sion gestational hypertension obesity preexisting and gesta-tional diabetes and cardiovascular conditions amongwomenof reproductive age should become a priority if we are tofurther improvematernal health and reduce health disparitiesin the United States [35] Further research is needed to assessthe role of social behavioral and environmental factorsresponsible for ethnic immigrant and sociodemographicdisparities in maternal hypertension

Disclosure

Theviews expressed are the authorsrsquo and not necessarily thoseof the US Department of Health and Human Services or theHealth Resources and Services Administration

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] E J Roccella ldquoReport of the national high blood pressureeducation program working group on high blood pressure inpregnancyrdquo American Journal of Obstetrics amp Gynecology vol183 no 1 pp S1ndashS22 2000

[2] American College of Obstetricians and Gynecologists ldquoHyper-tension in pregnancy report of the American College ofObstetricians and Gynecologistsrsquo Task Force on Hypertension

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

International Journal of Hypertension 13

in PregnancyrdquoObstetrics amp Gynecology vol 122 no 5 pp 1122ndash1131 2013

[3] R Mustafa S Ahmed A Gupta and R C Venuto ldquoA com-prehensive review of hypertension in pregnancyrdquo Journal ofPregnancy vol 2012 Article ID 105918 19 pages 2012

[4] K D Kochanek S L Murphy J Q Xu and B Tejada-VeraldquoDeaths final data for 2014rdquo National Vital Statistics Reportsvol 65 no 4 pp 1ndash121 2016

[5] N J Kassebaum A Bertozzi-Villa M S Coggeshall et alldquoGlobal regional and national levels and causes of maternalmortality during 1990ndash2013 a systematic analysis for the GlobalBurden ofDisease Study 2013rdquoTheLancet vol 384 no 9947 pp980ndash1004 2014

[6] M Tanaka G Jaamaa M Kaiser et al ldquoRacial disparity inhypertensive disorders of pregnancy in New York state a 10-year longitudinal population-based studyrdquo American Journal ofPublic Health vol 97 no 1 pp 163ndash170 2007

[7] L C Vinikoor-Imler S C Gray S E Edwards and ML Miranda ldquoThe effects of exposure to particulate matterand neighbourhood deprivation on gestational hypertensionrdquoPaediatric and Perinatal Epidemiology vol 26 no 2 pp 91ndash1002012

[8] D Hayes R Shor E Roberson and L Fuddy Maternal HighBlood Pressure and Pregnancy Fact Sheet Hawaii Departmentof Health Family Health Services Division Honolulu HawaiiUSA 2010

[9] J A Martin B E Hamilton M J K Osterman A K Driscolland T J Mathews ldquoBirths final data for 2015rdquo National VitalStatistics Reports vol 66 no 1 pp 1ndash69 2017

[10] J A Martin B E Hamilton M J K Osterman S C Curtinand T J Mathews ldquoBirths final data for 2012rdquo National VitalStatistics Reports vol 62 no 9 pp 1ndash68 2013

[11] G K Singh A Rodriguez-Lainz andM D Kogan ldquoImmigranthealth inequalities in the United States use of eight majornational data systemsrdquo The Scientific World Journal vol 2013Article ID 512313 21 pages 2013

[12] G Ghosh J Grewal T Mannisto et al ldquoRacialethnic differ-ences in pregnancy-related hypertensive disease in nulliparouswomenrdquo Ethnicity and Disease vol 24 no 3 pp 281ndash289 2014

[13] J Gong D A Savitz C R Stein and S M Engel ldquoMaternalethnicity and pre-eclampsia in New York City 1995ndash2003rdquoPaediatric and Perinatal Epidemiology vol 26 no 1 pp 45ndash522012

[14] US Census BureauThe American Community Survey US Cen-sus Bureau Washington DC USA 2016 httpwwwcensusgovacswww

[15] National Center for Health Statistics National Vital StatisticsSystem 2012ndash2014 Natality Public Use Files and User Guide USDepartment of Health and Human Services Hyattsville MdUSA 2015

[16] C Keating ldquoEclampsia causes symptoms and treatmentrdquoMedical News Today March 2017 httpswwwmedicalnewsto-daycomarticles316255php

[17] National Center for Health Statistics Guide to Completing theFacility Worksheets for the Certificate of Live Birth and Report ofFetal Death (2003 Revision) CDCNational Center for HealthStatistics Hyattsville Md USA 2016

[18] National Center for Health Statistics Motherrsquos Worksheet forChildrsquos Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[19] National Center for Health Statistics Facility Worksheet forthe Live Birth Certificate National Center for Health StatisticsHyattsville Md USA 2016

[20] SAS Institute Inc SASSTAT Userrsquos Guide Version 93 TheLOGISTIC Procedure SAS Institute Inc Cary NC USA 2011

[21] G K Singh and S C Lin ldquoDramatic increases in obesity andoverweight prevalence among Asian subgroups in the UnitedStates 1992ndash2011rdquo ISRN Preventive Medicine vol 2013 ArticleID 898691 12 pages 2013

[22] G K Singh and S C Lin ldquoMarked ethnic nativity andsocioeconomic disparities in disability and health insuranceamong US children and adultsrdquo BioMed Research Internationalvol 2013 Article ID 627412 17 pages 2013

[23] J N Pearcy and K G Keppel ldquoA summary measure of healthdisparityrdquo Public Health Reports vol 117 no 3 pp 273ndash2802002

[24] G K Singh M D Kogan M Siahpush and P C Van DyckldquoPrevalence and correlates of state and regional disparitiesin vigorous physical activity levels among US children andadolescentsrdquo Journal of Physical Activity amp Health vol 6 no 1pp 73ndash87 2009

[25] D L Blackwell J W Lucas and T C Clarke ldquoSummary healthstatistics for US adults National Health Interview Survey2012rdquoVital and Health Statistics vol 10 no 260 pp 1ndash161 2014

[26] National Center for Health Statistics The National HealthInterview Survey Questionnaires Datasets and Related Docu-mentation 2010ndash2014 Public Use Data Files US Department ofHealth and Human Services Hyattsville Md USA 2015

[27] L M Silva M Coolman E A P Steegers et al ldquoMaternaleducational level and risk of gestational hypertension theGeneration R Studyrdquo Journal of Human Hypertension vol 22no 7 pp 483ndash492 2008

[28] A Heshmati G Mishra and I Koupil ldquoChildhood and adult-hood socio-economic position and hypertensive disorders inpregnancy The uppsala birth cohort multigenerational studyrdquoJournal of Epidemiology and Community Health vol 67 no 11pp 939ndash946 2013

[29] G K Singh and R A Hiatt ldquoTrends and disparities insocioeconomic and behavioural characteristics life expectancyand cause-specific mortality of native-born and foreign-bornpopulations in the United States 1979ndash2003rdquo InternationalJournal of Epidemiology vol 35 no 4 pp 903ndash919 2006

[30] G K Singh M Siahpush and M D Kogan ldquoNeighborhoodsocioeconomic conditions built environments and childhoodobesityrdquo Health Affairs vol 29 no 3 pp 503ndash512 2010

[31] T D Bilhartz and P Bilhartz ldquoOccupation as a risk factorfor hypertensive disorders of pregnancyrdquo Journal of WomenrsquosHealth vol 22 no 2 pp 188andash188i 2013

[32] N Haghighat M Hu O Laurent J Chung P Nguyen and JWu ldquoComparison of birth certificates and hospital-based birthdata on pregnancy complications in Los Angeles and OrangeCounty Californiardquo BMC Pregnancy and Childbirth vol 16 no1 article 93 2016

[33] C V Ananth ldquoPerinatal epidemiologic research with vitalstatistics data validity is the essential qualityrdquoAmerican Journalof Obstetrics amp Gynecology vol 193 no 1 pp 5-6 2005

[34] M T Lydon-Rochelle V L Holt V Cardenas et al ldquoThereporting of pre-existing maternal medical conditions andcomplications of pregnancy on birth certificates and in hospitaldischarge datardquo American Journal of Obstetrics amp Gynecologyvol 193 no 1 pp 125ndash134 2005

14 International Journal of Hypertension

[35] National Center for Health StatisticsHealth United States 2015with Special Feature on Racial and Ethnic Health Disparities USDepartment of Health and Human Services Hyattsville MdUSA 2016

Stem Cells International

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

MEDIATORSINFLAMMATION

of

EndocrinologyInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Disease Markers

Hindawiwwwhindawicom Volume 2018

BioMed Research International

OncologyJournal of

Hindawiwwwhindawicom Volume 2013

Hindawiwwwhindawicom Volume 2018

Oxidative Medicine and Cellular Longevity

Hindawiwwwhindawicom Volume 2018

PPAR Research

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Immunology ResearchHindawiwwwhindawicom Volume 2018

Journal of

ObesityJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Computational and Mathematical Methods in Medicine

Hindawiwwwhindawicom Volume 2018

Behavioural Neurology

OphthalmologyJournal of

Hindawiwwwhindawicom Volume 2018

Diabetes ResearchJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Research and TreatmentAIDS

Hindawiwwwhindawicom Volume 2018

Gastroenterology Research and Practice

Hindawiwwwhindawicom Volume 2018

Parkinsonrsquos Disease

Evidence-Based Complementary andAlternative Medicine

Volume 2018Hindawiwwwhindawicom

Submit your manuscripts atwwwhindawicom

Stem Cells International

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

MEDIATORSINFLAMMATION

of

EndocrinologyInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Disease Markers

Hindawiwwwhindawicom Volume 2018

BioMed Research International

OncologyJournal of

Hindawiwwwhindawicom Volume 2013

Hindawiwwwhindawicom Volume 2018

Oxidative Medicine and Cellular Longevity

Hindawiwwwhindawicom Volume 2018

PPAR Research

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Immunology ResearchHindawiwwwhindawicom Volume 2018

Journal of

ObesityJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Computational and Mathematical Methods in Medicine

Hindawiwwwhindawicom Volume 2018

Behavioural Neurology

OphthalmologyJournal of

Hindawiwwwhindawicom Volume 2018

Diabetes ResearchJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Research and TreatmentAIDS

Hindawiwwwhindawicom Volume 2018

Gastroenterology Research and Practice

Hindawiwwwhindawicom Volume 2018

Parkinsonrsquos Disease

Evidence-Based Complementary andAlternative Medicine

Volume 2018Hindawiwwwhindawicom

Submit your manuscripts atwwwhindawicom