Introduction UK guidelines advocate that obese pregnant women (body mass index, BMI ≥30 kg/m2) be made aware of the increased risks to them and their offspring. This study hence pooled data from several sources to derive estimates of the absolute and attributable risks of stillbirth and infant death for obese women in England, and predict changes in prevalence resulting from trends in BMI.
Methods The BMI profile of the maternal population of England and of the prevalence of each outcome were obtained from nationally representative sources. Trends in BMI were modelled by logistic regression. RRs for stillbirth and infant death were derived from published literature. These were equated to estimate absolute risks, attributable risks, and future prevalence rates.
Results The estimated absolute risk of a stillbirth or infant death for an obese pregnant woman in England is 1.5% (95% CI 1.3 to 1.8), compared to 0.9% (0.8 to 0.9) for women of recommended BMI (25–29 kg/m2). An estimated 8.1% of stillbirths and infant deaths in England are attributable to maternal obesity.
If trends in maternal BMI continue, 24.0% (22.1 to 25.9) of the maternal population of England will be obese by 2020. This is predicted to result in a 4.4% increase in the prevalence of stillbirth and infant death compared to 2010.
Conclusion This study provides estimates of the individual risk and population burden of stillbirth and infant death in England resulting from maternal obesity. These results have implications for public health planning and for providing clear information to obese women about their pregnancy-related risks.