Dietary and Lifestyle Interventions in Obese Pregnant Women

Background: Maternal obesity is associated with higher risks of adverse maternal and fetal complications, but the effects of dietary and lifestyle interventions on gestational weight gain(GWG) and pregnancy outcomes in obese pregnant women are unclear.

Objective: This study examined whether intensive dietary and lifestyle interventions initiated in the early pregnancy could decrease GWG, and prevent relevant adverse pregnancy outcomes in Chinese obese pregnant women.

Design:A randomized controlled trial in obese pregnant women was performed at 6-12 weeks of gestation.The sample size was estimated using GWG reduction as the primary outcome variable. The investigators pilot study (data not published) showed the gestational weight gain was 12.73±5.97 for obese women. Assuming intervention may result in 25% (3.1825g) reduction in GWG, the estimated sample size with 90% power and type I error of 0.05 was 114 women in intervention group and 57 in control group. Adjusting for 15% refusal or loss to follow up during pregnancy, the total sample size required was 136 women in intervention group and 68 in control group(standard care group). Participants were randomly assigned to the control or the intervention group. The intervention focused on restricting energy intake combined with behavioral lifestyle modification through participation in group sessions and individual counseling. The primary outcomes were gestational weight gain (GWG) and secondary outcomes were the incidence of gestational diabetes mellitus (GDM), hypertensive disorders during pregnancy, large-for-gestational-age (LGA) infants, macrosomia and the rate of caesarian section.

Hypothesis:The intensive dietary and lifestyle intervention performed from the first trimester in obese women could decrease total GWG,and perhaps improve relevant pregnancy outcomes.