Impact of preconception weight loss on fasting glucose and pregnancy outcomes in women with obesity: A randomized trial

Abstract

Objective: This study examined the effectiveness of a nonsurgical, preconception weight loss intervention on pregnancy outcomes in women with obesity. Methods: This was a two-arm, parallel-group randomized controlled trial. A total of 164 women with BMI 30 to 55 kg/m2 who were aged 18 to 38 years and planning pregnancy were randomized to a 12-week standard dietary intervention (SDI; n = 79) or a modified very low-energy diet (VLED; n = 85). Participants were observed for ≤48 weeks while trying for pregnancy and then during pregnancy. The primary outcome was maternal fasting plasma glucose at 26 to 28 weeks’ gestation. Exploratory outcomes were individual and composite obesity-related adverse pregnancy outcomes. Results: Weight loss was greater in the VLED group (SDI 3.2 [0.6] kg vs. VLED 13.0 [0.5] kg, p < 0.01). In completers who had a singleton live birth (SDI 22/79 vs. VLED 35/85, p = 0.10), there was no difference in fasting glucose at 26 to 28 weeks’ gestation (SDI 4.8[0.2] mmol/L vs. VLED 4.6 [0.1] mmol/L, p = 0.42). However, the composite of adverse pregnancy outcomes was significantly lower in the VLED group (p < 0.001). Conclusions: Substantial prepregnancy weight loss in women with obesity does not alter fasting glucose at 26 to 28 weeks’ gestation but does reduce a composite of adverse pregnancy outcomes. A better understanding of metabolic changes in pregnancy after preconception weight loss may assist in improving maternal and neonatal health outcomes.