Physical health and development of the child

The CEMACH report for the period 2003-2005 identifies the risks of maternal obesity to the child as:

• stillbirth
• neonatal death
• congenital anomalies
• prematurity

In 2005, 22.9% of mothers who had late foetal loss were obese, as were 30.4% of the women who experienced stillbirths, and 30.6% of those who experienced neonatal deaths [22].

These findings are consistent with published research showing an association between obesity during pregnancy and increased risk of:

• late foetal loss [23]
• stillbirth [24]
• congenital anomalies including:- neural tube defects, spina bifida, cardiovascular anomalies, septal anomalies, cleft lip and palate, anorectal atresia, hydrocephaly, limb reduction anomalies [25]

An explanation for the link between maternal obesity, increased stillbirths and late foetal loss could be the potential to misdiagnose conditions such as macrosomia or growth restriction in utero, leading to appropriate measures not being taken during delivery. Foetal distress may not be detected due to a reduced ability to accurately monitor the foetal heart rate during labour [14]. The increased risk of congenital anomalies may be linked to undiagnosed diabetes and hyperglycaemia in obese pregnant women [25] or to lower levels of circulating nutrients, specifically folate [26].

Other factors relating to the health of the baby include:

• macrosomia
• post-date and pre-term deliveries
• increased requirement for neonatal intensive care
• low Apgar score at five minutes, foetal distress [16]
• foetal growth restriction [27]

Women who are overweight or obese are less likely to have a live birth following in vitro fertilisation (IVF) than women who are not overweight [28][29].

Childhood obesity

It is well recognised that children who are obese are likely to have obese parents [30, 31]. Life course research suggests that adult health and inequalities can be influenced by the intra-uterine environment [32]. There is a significant relationship between maternal obesity, macrosomia, and the subsequent development of childhood and adult obesity in their offspring [33-37]. A systematic review of the childhood predictors of adult obesity showed that maternal obesity and weight gain during pregnancy are related to higher BMI in childhood and subsequent obesity in adulthood [30].

When women are obese, they also have an increased risk of type I diabetes, impaired glucose tolerance (IGT), and gestational diabetes mellitus (GDM) [38]. Life course studies show that women who have diabetes during pregnancy are likely to have obese offspring. This is independent of genetic factors suggesting that the intra-uterine environment is altered in a diabetic pregnancy [33, 39-43]. The mechanisms by which these endogenous factors lead to the development of childhood obesity are not known but there are multiple theories regarding the effects of the intra-uterine environment.