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, for pregnant women, including those who are overweight and obese, according to a new study. In the UK, more than half the women of reproductive age are overweight or obese, and across Europe and the US, up to 40 per cent 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 researchers 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 researchers concluded 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.