DID THE STRESS OF THE JFK ASSASSINATION AFFECT BIRTH WEIGHTS OF

THE OFFSPRING FROM EXPOSED MOTHERS?

AuthorAuthorAuthor

The effect of a population-wide stress event during

pregnancy and pre-conception

Hypothesis:

A widespread stressor (the assassination of John F Kennedy on Friday, November 22, 1963) will result in lower birth weights of infants from mothers exposed to the event while pregnant or pre-conception.

Exposure and Outcomes

Exposure: Population-wide stressor

(JFK assassination)

Outcome: Birth weight of exposed infantsPre-term birth (secondary

outcome)

Why is this important

LBW is associated with other poor health outcomes Perinatal morbidity/mortality Delayed cognitive and motor development Chronic disease risk

Identifying risk factors for low birth weight

Possible direction for interventions

By reducing LBW, reduce long term health impacts

What is known:

Literature review suggests that stress is associated with: LBW and Very LBW Pre-term labor Reduced secondary sex ratio

Adrenal and pituitary stress hormones Risk for fetal growth retardation Preterm Birth

What will we contribute?

Studies on adverse exposures during pregnancy limited to observational studies. Chronically stressed differ from general

population.

No known studies examining the effect of the JFK assassination on birth outcomes

Apply new theories and information about maternal stress to a historical cohort

Contributes to the body of research linking maternal stress to birth outcomes

All pregnancies from the Child Health and Development Studies Database

N=20754

All pregnancies from the Child Health and Development Studies Database

N=20754

Only singleton birthsN=20307

Twins and triplets: 447 removed

All pregnancies from the Child Health and Development Studies Database

N=20754

Only singleton birthsN=20307

Only live birthsN=18582

Twins and triplets: 447 removed

Stillborn infants: 1725 removed

All pregnancies from the Child Health and Development Studies Database

N=20754

Only singleton birthsN=20307

Only live birthsN=18582

Only infants w/out severe anomaliesN= 17939

Twins and triplets: 447 removed

Stillborn infants: 1725 removed

Infants with one or more severe anomalies:

643 removed

All pregnancies from the Child Health and Development Studies Database

N=20754

Only singleton birthsN=20307

Only live birthsN=18582

Only infants w/out severe anomaliesN= 17939

Twins and triplets: 447 removed

Stillborn infants: 1725 removed

Infants with one or more severe anomalies:

643 removed

Only infants conceived before 8/27/1964

N=14553

Conceived after 8/27/1964: 3386 removed

Population studied: 14553 singleton, live born infants with no severe

anomalies conceived before 8/27/1964.

Population studied: 14553 singleton, live born infants with no severe

anomalies conceived before 8/27/1964.

Unexposed infants:

10,693

Population studied: 14553 singleton, live born infants with no severe

anomalies conceived before 8/27/1964.

Exposed in utero:

2,132

1st Trimester: 6672nd Trimester: 7063rd Trimester: 759

Unexposed infants:

10,693

Population studied: 14553 singleton, live born infants with no severe

anomalies conceived before 8/27/1964.

Exposed in utero:

2,132

1st Trimester: 6672nd Trimester: 7063rd Trimester: 759

Unexposed infants:

10,693

Exposed pre-conception:

1,728

Conceived:1-3 mos post: 748 >3-6 mos post: 538>6-9 mos post: 442

Main Exposure Variable

Exposure to Assassination Not exposed:

infant born before November 22, 1963

Exposed in utero: infant conceived before November 22, 1963 and born after Nov 22, 1963.

Exposed during pre-conception: infant conceived within 9 months after

November 22, 1963

Results: Demographic Characteristics

Maternal Characteristic P-value Sketch

Direction of Difference

Race: Black, White Other <0.0001

~20-25% Black

~10% Other

Black and Other

Marital status:Married or Not <0.0001

4, 6 and 8% Unmarried

Unmarried

Smoking <0.0001~45-50%

nonsmokers Non Low

Nulliparous or Not nulliparous 0.002 ~30%

Nulliparous Nulliparous

Maternal AgeOver/Under 35 0.02 <35 ~85% ≥35

Results: Demographic Characteristics

Maternal Characteristic P-value Sketch

Direction of Difference

Maternal Stress

0.80 ~10% stressed

No change

HypertensionPreeclampsia

0.810.11

Rare:~0.6%~2-3%

Slight increase

in preeclampsia

Social Status 0.13 ~35-38% LMC

No change

Alcohol 0.95 ~60% non-drink

No change

Less than 18.518.5 – 29.9More than 30

0.47~90%

18.5-29.9 No change

Covariates with P < 0.20 in univariate analysis

Maternal Characteristics

Race*Marital Status*Age*Parity*Smoking*PreeclampsiaStressSocial Status*

Infant Characteristics

Sex*Gestational Age*

Not significantAlcohol

*=P <0.0001

Multivariate Linear Regression:

Infant covariates Gestational age (continuous) Sex

i = missing data imputed using linear regression

Maternal covariates Age (continuous) Alcoholi

Marital statusi

Nulliparous Pre-eclampsia Negative attitude toward

pregnancy

BMIi (3) Race (3) Smokingi (4) SESi (5)

Exposed to assassination (3)

β for factors associated with lower birth weight (g)

BlackOther Non-White

Preeclampsia

Hi SmokeMed SmokeLow Smoke

Low BMI (<18.5)

L ClassLMC

-250.0 -200.0 -150.0 -100.0 -50.0 0.0

P = 0.03

*

*

* =P <0.0001

*

*

**

β for factors associated with higher birth weight (g)

Maternal Age (years)

Not Nulliparous

High BMI (≥30)

Gestational Age (weeks)

Male Infant

0.0 50.0 100.0 150.0 200.0 250.0

P=0.002

*

* =P <0.0001

*

*

*

Coefficients (in grams) for non-significant findings

P=0.10

Exp In-utero

Exp Pre-conception

Upper Class

Upper Middle Class

Married

Stressed Mother

Drinker

-40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0

Coefficients for exposure groups in grams

Exposed in Utero Exposed Pre-Conception

-30

-25

-20

-15

-10

-5

0

5

10

3.5

-25.4

CI: (-25.8, 32.7)P=.82

CI: (-55.9, 5.1) P=.10

Odds of low birth weight not statistically significant with respect to

exposure

Mean difference in birth weight not statistically significant with respect to

exposure

Mean difference in gestation length not statistically significant with respect to

exposure

Limited number of births in the weeks post assassination limit ability to study premature

births

Limitations of Study

Inadequate exposure characterization Limitations of data collection Assessment of JFK Assassination as unique

acute stressor

Limited statistical power over critical time intervals

Conclusions and Future Directions

Unable to detect the effect of the assassination on early parturition

Model suggests exposure pre-conception may have small effect on birth weight

To address this question further we must: Examination of the JFK assassination in a

larger study population Examine effects of other acute stressors on

birth outcomes

References

Cottrell EC, Seckl JR, Baram TZ. Prenatal stress , glucocorticoids and the programming of adult disease. Behavioral Neuroscience. 2009;3(September):1-9.

McCarton CM, Brooks-Gunn J, Wallace IF, et al. Results at age 8 years of early intervention for low-birth-weight premature infants. The Infant Health and Development Program. JAMA : the journal of the American Medical Association. 1997;277(2):126-32.

McCarton CM, Brooks-Gunn J, Wallace IF, et al. Results at age 8 years of early intervention for low-birth-weight premature infants. The Infant Health and Development Program. JAMA : the journal of the American Medical Association. 1997;277(2):126-32.

Whitaker AH, Feldman JF, Lorenz JM, et al. Motor and cognitive outcomes in nondisabled low-birth-weight adolescents: early determinants. Archives of pediatrics & adolescent medicine. 2006;160(10):1040-6.

Whitaker AH, Feldman JF, Lorenz JM, et al. Motor and cognitive outcomes in nondisabled low-birth-weight adolescents: early determinants. Archives of pediatrics & adolescent medicine. 2006;160(10):1040-6.

Wadhwa PD, Dunkel-Schetter C, Chicz-DeMet A, Porto M, Sandman CA. Prenatal psychosocial factors and the neuroendocrine axis in human pregnancy. Psychosomatic medicine. 1996 ;58(5):432-46.

Wadhwa PD, Dunkel-Schetter C, Porto M, et al. Psychobiological processes and prenatal stress in human pregnancy. Ann. Behav. Med. 1997a;19S:39.

Wadhwa PD, Sandman CA, Chicz-DeMet A, et al. Placental CRH modulates maternal pituitary adrenal function in human pregnancy. Ann. New York Acad. Sci. 1997b;814:276-281.

Wadhwa PD, Herbel K, Dunkel-Schetter C, et al. Prenatal stress and infant development: a preliminary study. Ann. Behav. Med. 1998a;20: SO29.

Wadhwa PD, Porto M, Garite TJ, et al. Maternal CRH levels in the early third trimester predict length of gestation in human pregnancy. Am. J. Obstet. Gynecol. 1998b; 179: 1079-1085.

Wadhwa PD, Garite TJ, Porto M, et al. Placental corticotropin-releasing hormone (CRH), spontaneous preterm birth, and fetal growth restriction: A prospective investigation. American Journal of Obstetrics & Gynecology. 2004;19(4):1063-1069

Challis JR, Smith SK. Fetal endocrine signals and preterm labor. [Internet]. Biology of the neonate. 2001 Jan ;79(3-4):163-7.

References Continued

Hillhouse E, Grammatopoulos DK. Role of stress peptides during human pregnancy and labour [Internet]. Reproduction. 2002 Sep ;124(3):323-329.

Wadhwa PD. Psychoneuroendocrine processes in human pregnancy influence fetal development and health. [Internet]. Psychoneuroendocrinology. 2005 Sep ;30(8):724-43.

Copper RL, Goldenberg RL, Das A, et al. The preterm prediction study: Maternal stress is associated with spontaneous preterm birth at less than thirty-five weeks’ gestation. American Journal of Obstetrics & Gynecology. 1996;175(5):1286-1292.

Eskenazi B, Marks AR, Catalano R, Bruckner T, Toniolo PG. Low birth weight in New York City and upstate New York following the events of September 11th. Human reproduction (Oxford, England). 2007;22(11):3013-20.

Catalano R, Bruckner T, Marks a R, Eskenazi B. Exogenous shocks to the human sex ratio: the case of September 11, 2001 in New York City. Human reproduction (Oxford, England). 2006;21(12):3127-31.

Wolff MS, Teitelbaum SL, Lioy PJ, et al. Exposures among Pregnant Women near the World Trade Center Site on 11 September 2001. Environmental Health Perspectives. 2005;113(6):739-748.

Tan CE, Li HJ, Zhang XG, et al. The impact of the Wenchuan earthquake on birth outcomes. PloS one. 2009;4(12):e8200.

US Census Bureau, Table 5 West Region- Race and Hispanic Origin 1850-1990. http://www.census.gov/population/www/documentation/twps0056/twps0056.html Updated 1990. Accessed November 28, 2010.

Eskenazi B, Marks AR, Catalano R, Bruckner T, Toniolo PG. Low birth weight in New York City and upstate New York following the events of September 11th. Human reproduction (Oxford, England). 2007;22(11):3013-20.

Goldenberg RL, P S, Mulvihill FX, et al. Medical , psychosocial , and behavioral risk factors do not explain the increased risk for low birth weight among black women. American Journal of Obstetrics & Gynecology. 1996;175:1317-1324.

Hollingshead AB. Two factor Index of Social Position. New Haven CT: Yale Station; 1965 Morrow-Tlucak M, Ernhart CB, Sokol RJ, Martier S, Ager J. Underreporting of alcohol use in pregnancy:

relationship to alcohol problem history. Alcoholism, clinical and experimental research. 1989;13(3):399-401. Ginwright SA. Black in School. New York, NY: Teachers College Press; 2004 Littleton HL, Bye K, Buck K, Amacker A. Psychosocial stress during pregnancy and perinatal outcomes: a meta-

analytic review. J Psychosom Obstet Gynaecol. 2010;31(4):219-228.)

Figure 2: Time periods examined

PC 1

PC 3 PC 2

3rd 2nd

1st

Unexposed

JFK AssassinationNovember 22,

1963

Removed from data set

Exposed pre-conception

Exposed In -Utero