1. Underweight pregnant women in low risk populations: Does a low BMI (<18.5) predict adverse pregnancy outcomes?
Paul de Cock
AIRC2012

2. Midwifery Academy Amsterdam Groningen (AVAG)
VU University Medical Center
EMGO Instituut - Care and Prevention

3. 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

4. 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.

5. 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.

6. 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?

7. 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)

8. Low BMI – lowered risk of…
Reduced risk of complications, such as:
Gestational diabetes mellitus
Pre-eclampsia
Obstetric intervention
Postpartum haemorrhage
(Sebire et al., BMI<20)

9. Low BMI in low-risk population
Research question:
What are the pregnancy outcomes of low-risk underweight women in primary midwifery care?

10. 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)
Zwangerschapsuitkomsten:
Zwangerschapsduur
Geboortegewicht

11. 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

12. Method - outcomes Neonatal Weight
Weight percentile (<2.3; <5.0; <10)
APGAR <7 after 5 minutes
Consult with paediatrician

13. Results – Pregnancy outcomes
Low BMI (<18,5)
Normal BMI (>18,5-24,99)
P-value
Hypertension yes no
1 156
0 157 -
Hb 1st consult (mmol/l)
7,54
7,74
<0,05*
Hb 30 weeks (mmol/l)
7,09
7,29
Hb 1st consult <7,1 mmol/l
yes No
30 127
17 140
0,058
Hb 30 weeks <6,3 mmol/l yes no
11 146
3 154
Consulted obstetrician during pregnancy
yes no
43 115
29 128
0,099
Suspected IUGR
Ja Nee
9 148
0,655
Disturbed glucose levels Ja Nee
0,317

14. Results – Birth outcomes
Low BMI <18,5
Normal BMI (>18,5-24,99)
P-value
Gestation (days)
277,38
277,80
0,840
Prematurity yes no
8 149
1,000
Instrumental delivery
yes no
23 134
15 142
0,194
Total blood loss (ml)
403,67
389,81
0,717
Active management of placental delivery
yes no
not known
100
43 14
0,676
0,673
<0,05*

15. Results – Neonate outcomes
Low BMI <18,5
Normal BMI (>18,5-24,99)
P-value
Gender boy girl
88 69
76 81
0,349b 0,327b
Birth weight (grammes)
2878,48
3532,68
<0,05*a
Birth weight
percentile
12,62
45,39
<2,3 yes no suspected IUGR
<5,0 yes no suspected IUGR
<10 yes no suspected IUGR
(13,6 %)
(11,3%)
(9,1%)
(16,6%)
(16,7%)
(17,6%)
<0,05*b
APGAR score < 7 after 5 minutes yes no
4 153 3
154
0,705b
Consulted Peadiatrician
yes no
31 126
43 114
0,198b

16. 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

17. 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.

18. Thank you for listening
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,
b Midwifery Academy Amsterdam Groningen, The Netherlands; T: , F: ,