Dieting in pregnancy can be beneficial and reduce complications

May 21 2012

For pregnant women, including those who are overweight and obese, following a healthy calorie controlled diet during pregnancy is safe and can reduce the risk of serious complications such as pre-eclampsia, diabetes and premature birth, finds a study published on bmj.com.

In the UK, more than half the women of reproductive age are overweight or obese, and across Europe and the US, up to 40% of women gain more than the recommended weight in pregnancy. Excessive weight gain during pregnancy is associated with a number of serious health problems.

Pregnancy is thought to be an ideal time for health professionals to discuss weight management as mothers are motivated to make changes that will benefit themselves and their baby.

So a team of researchers, led by Dr Shakila Thangaratinam from Queen Mary, University of London, investigated the effects of diet, exercise, or a combination of the two on weight gain during pregnancy and any adverse effects on mother or baby.

They analysed the results of 44 randomised controlled trials involving over 7,000 women. Study design and quality were taken into account to minimise bias.

Weight management interventions in pregnancy were effective in reducing weight gain in the mother. Dietary intervention resulted in the largest average reduction in weight gain (almost 4 kg) compared with just 0.7 kg for exercise and 1 kg for a combination of the two. Diet also offered the most benefit in preventing pregnancy complications such as pre-eclampsia, diabetes, high blood pressure and premature birth.

However, the authors stress that the overall evidence rating was low to very low for these important outcomes.

Importantly, the results showed that  interventions are safe and do not adversely affect the baby’s weight. The authors conclude that dietary and lifestyle interventions in pregnancy improve outcomes for both mother and baby, but acknowledge the lack of data on risk factors such as age, ethnicity and socioeconomic status.

However, in an accompanying editorial, experts at St Thomas’ Hospital in London say there is not yet sufficient evidence to support any particular intervention.

Lucilla Poston and Lucy Chappell suggest that although this study is “timely and welcome”, it does not provide the evidence needed for the National Institute for Health and Clinical Excellence (NICE) to reassess the guidelines for weight management in pregnancy.  They point to several ongoing trials that will enable a greater understanding of effective interventions in overweight and obese women