EMGO Institute for Health and Care Research
Quality of Care
Underweight pregnant women in low risk populations: Does a low BMI (<18.5) predict adverse pregnancy outcomes?
Paul de CockAIRC2012
• Midwifery Academy Amsterdam
Groningen (AVAG)
• VU University Medical Center
Echelon system in perinatal care
The Netherlands: echelon system in perinatal care
• 1st: community: monitored by independent midwife
• 2nd: hospital: gynaecologist & clinical midwife
• 3rd: academic referral centre: gynaecologist & clinical midwife
http://www.knov.nl/docs/uploads/Midwifery_in_The__Netherlands__20120730__groot.pdf
Midwifery care
• App. 184000 births in Netherlands
• A quarter of these are home births
• Antenatal care by Midwife in 79.6% of pregnancies
• Remaining pregnancies (20.4%) are under supervision of gynaecologist (hospital/secondary care)
– Half of these are because of a medical indication.
Risk selection in echelons
• Women with health complications or known health risks are referred to secondary care setting
• This means that there is a risk selection in primary care, which is effective.
• For low BMI women this means that only those with no known additional health risks are under supervision of a primary care midwife.
Reason for this research
• University of applied science keeps strong links with the field – the field is actively invited to submit research questions to the college
• Manager of a large midwifery practice asked about the risks attached to low BMI for pregnant women under supervision of a primary care midwife.
– Women with medical indications have been referred. Is there a risk for the remaining healthy low BMI women with regard to pregnancy outcomes for mother and baby?
Low BMI – risk
• Increased risk of miscarriage (Maconochie et al., 2007)
• Preterm birth (Han et al., 2011)
• Low birth weight (Han et al., 2011)
• Increased risk of anaemia (Sebire et al., 2007)
Low BMI – lowered risk of…
• Reduced risk of complications, such as:– Gestational diabetes mellitus
– Pre-eclampsia
– Obstetric intervention
– Postpartum haemorrhage
(Sebire et al., 2007 - BMI<20)
Low BMI in low-risk population
• Research question:
– What are the pregnancy outcomes of low-risk underweight women in primary midwifery care?
Method - sample
• Retrospective case-control database study
– 2 large midwifery practices
– All underweight (< 18.5) women on record (past 5 years)
– Controls matched on age, smoking, alcohol use, drug use
– Only controls with normal BMI were included (18.5 – 24.99)
Method - outcomes
• Maternal
– Hypertension
– Hb (1st consult and at 30 weeks)
– Suspected intrauterine growth retardation
• Birth outcomes
– Duration of pregnancy
– Prematurity
– Instrumental delivery
– Bloodloss
– Active management of placental delivery
Method - outcomes
• Neonatal
– Weight
– Weight percentile (<2.3; <5.0; <10)
– APGAR <7 after 5 minutes
– Consult with paediatrician
Results – Pregnancy outcomes
Low BMI (<18,5) Normal BMI (>18,5-24,99)
P-value
Hypertension yesno
1156
0157
-
Hb 1st consult (mmol/l) 7,54 7,74 <0,05*
Hb 30 weeks (mmol/l) 7,09 7,29 <0,05*
Hb 1st consult <7,1 mmol/l yesNo
30127
17140
0,058
Hb 30 weeks <6,3 mmol/lyesno
11146
3154
<0,05*
Consulted obstetrician during pregnancyyesno
43115
29128
0,099
Suspected IUGRJa Nee
11146
9148
0,655
Disturbed glucose levelsJaNee
1156
3154
0,317
Results – Birth outcomes
Low BMI <18,5 Normal BMI (>18,5-24,99)
P-value
Gestation (days) 277,38 277,80 0,840Prematurityyesno
8149
8149
1,000
Instrumental deliveryyesno
23134
15142
0,194
Total blood loss (ml) 403,67 389,81 0,717Active management of placental deliveryyesnonot known
1004314
106474
0,6760,673<0,05*
Results – Neonate outcomes
Low BMI <18,5 Normal BMI (>18,5-24,99)
P-value
Genderboygirl
8869
7681
0,349b0,327b
Birth weight (grammes) 2878,48 3532,68 <0,05*a
Birth weightpercentile
12,62 45,39 <0,05*a
Birth weightpercentile<2,3yesnosuspected IUGR
<5,0yesnosuspected IUGR
<10yesnosuspected IUGR
441136 (13,6 %)
71868 (11,3%)
99589 (9,1%)
61511 (16,6%)
121452 (16,7%)
171403 (17,6%)
<0,05*b
<0,05*b
<0,05*b
APGAR score < 7 after 5 minutesyesno
4153
3154
0,705b
Consulted Peadiatricianyesno
31126
43114
0,198b
Discussion
• Women with low BMI at increased risk of anaemia.
• Babys are smaller, but no raised levels of suspected IUGR, poor APGAR scores or consults with paediatrician.
• No difference in prematurity found in this study
Conclusion
• On the basis of this study pregancy outcomes do not appear to differ much between women with low and normal BMI in primary care.
• More research is being done in a large prospective cohort study (DELIVER) to assess a broader range of outcomes in a large national sample.
• Paul de Cock PhD ab, Willemijn Perdijk b, MA RM, Aresh Mohammadi BA RM b, Elise Neppelenbroekb, Ingrid Hollemab
Thank you for listening
• a Department of Midwifery Science, AVAG and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands, [email protected].
• b Midwifery Academy Amsterdam Groningen, The Netherlands; T: +31 50- 3618886, F: + 31 50-3619930,
