Healthy weight in pregnancy

Maternal obesity has become one of the most commonly occurring risk factors in obstetric practice. Obesity in pregnancy is usually defined as a body mass index (BMI) of 30 kg/m² or more at the first antenatal consultation.

Risks of maternal obesity to the health of mother and child

Maternal obesity increases health risks for both the mother and child during and after pregnancy. Risks to the mother include maternal death or severe morbidity, cardiac disease, miscarriage, pre-eclampsia, gestational diabetes, haemorrhage and infection. There is also evidence of an association between maternal obesity and low breastfeeding rates. The risks to the child of obesity during pregnancy include stillbirth and neonatal death, prematurity and congenital anomalies. Obesity in pregnancy can also affect health later in life for both mother and child. For the mother, these risks include heart disease and hypertension. Children have a risk of future obesity and heart disease. Mother and child are at increased risk for diabetes. Maternal obesity can increase need for healthcare due to complications including increases in caesarean deliveries, hospital admissions for complications, increased length of stay for mother and baby, and requirements for neonatal intensive care.

Prevalence

Both locally and nationally, there is a lack of routine data on the prevalence of maternal obesity. Trend data from the Health Survey for England show an increase in the prevalence of obesity amongst women of childbearing age (16 to 44 years) from around 12% in 1993 to almost 20% in 2010. One recent study (Heslehurst et al, 2010), designed to be representative of England as a whole, estimated that the prevalence of first trimester maternal obesity increased significantly from 7.6% in 1989 to 15.6% in 2007. Health inequalities were also identified, with the risk of maternal obesity increasing with increasing deprivation.

References

Heslehurst et al (2010). A nationally representative study of maternal obesity in England, UK: trend in incidence and demographic inequalities in 619,323 births, 1989-2007. Int J Obes; 34(3):420-8

Page updated November 2012