Antenatal lifestyle advice for women who are overweight or obese: LIMIT randomised trial

Overweight and obesity are common during pregnancy, with ~50% of women entering pregnancy with a body mass index (BMI) of 25 or greater. Numerous maternal and fetal risks and complications associated with overweight/obesity during pregnancy are documented, as well as the negative impact of excess gestational weight gain. This randomized study was performed to evaluate whether providing antenatal lifestyle advice to overweight or obese pregnant women would improve maternal and infant outcomes. Women were enrolled in 2009 to 2011 if they had a BMI of 25 or greater and singleton pregnancy at 10 to 20 weeks’ gestation. The women in the lifestyle advice group received comprehensive information encompassing dietary, exercise, and behavioral strategies. The women randomized to the standard group received care according to local perinatal practices, which did not include routine advice related to diet, exercise, or gestational weight gain. The primary outcome was the incidence of infants born large for gestational age (LGA; birth weight Q90th percentile for gestational age and infant sex). Prespecified secondary maternal and infant outcomes were assessed. In a post hoc analysis, gestational weight gain was categorized as the proportion of women whose weight gain was lower than, was within, or exceeded the Institute of Medicine recommendations based on early BMI category. Analyses were performed on an intentionto-treat basis. The analysis included 2152 women and 2142 live-born infants. The BMI of the cohort was 31.1 (interquartile range, 27.9–35.8); 42.1% of the women were overweight and 57.9% were obese. No significant difference was found in the risk for infants born LGA in the advice group compared with the standard group (203/1075 [19%] vs 224/1067 [21%]; P = 0.24). Infants born to the women in the advice group were less likely to weigh greater than 4000 g (n = 164 [15%] vs n = 201 [19%]; P = 0.04) compared with infants born to the women in the standard group. The groups did not differ significantly in preterm birth before 37 weeks; infant admission to the NICU or special care unit; or maternal risk for antenatal, labor, or birth complications. Post hoc analysis found no difference in total gestational weight gain in the lifestyle advice and standard care groups (mean [SD], 9.39 [5.74] kg and 9.44 [5.77] kg, respectively; P = 0.89). No significant differences were apparent in the proportion of women whose weight gain was lower than, was within, or exceeded the Institute of Medicine recommendations based on BMI in early pregnancy. Providing lifestyle advice to overweight or obese women during pregnancy did not reduce the risk for infants born LGA or improve maternal outcomes of pregnancy and birth but was associated with a small but significant reduction in the risk of birth weight of greater than 4000 g. Although a more intensive intervention might be effective in modifying these risks, important considerations include the cost of providing interventions and maternal compliance.