Obesity in pregnancy is a growing problem. Nationwide, about one in five expectant mothers is obese, and up to 40 percent of women gain more weight than recommended during pregnancy.
But many experts worry that dieting can carry risks during pregnancy, including complications like low birth weight and preterm delivery, although a number of studies over the years have provided largely inconsistent results. To find a more definitive answer, British researchers recently carried out a meta-analysis that pooled data from 44 randomized studies involving more than 7,000 pregnant women, most of them overweight or obese. The studies looked at the effects of diet, exercise — mainly light resistance training and walking — and other lifestyle interventions on maternal weight and pregnancy outcomes.
Over all, the team found that the diets that were most effective at limiting weight gain among expectant mothers emphasized whole grains, beans, fruits and vegetables, and lean protein. The study, published in the journal BMJ, also found that such a diet — as long as it was “balanced” and tailored to nutritional needs — lowered the risk of complications.
Compared with other overweight women, those who went on a diet had a 61 percent lower risk of gestational diabetes and a 33 percent lower risk ofpre-eclampsia, which causes dangerous increases in blood pressure in pregnant women. They also had lower rates of gestational hypertensionand preterm delivery.