OBJECTIVETo evaluate the associations between pregestational body mass index (BMI), weight gain during first half of pregnancy and the risk for gestational diabetes mellitus (GDM).

METHODSA prospective cohort study was conducted among 1,914 local pregnant women, receiving the first prenatal examination during the first 14 weeks of gestation, in Ma'anshan of Anhui province from May 2013 to September 2014. The body weight and height were measured for these pregnant women and questionnaire surveys were conducted among them at enrollment, middle gestation and late gestation, respectively. During 24-28 week of gestation, 75 g oral glucose tolerance test was conducted for them. The independent and joint associations between pregestational BMI/weight gain and the risk of GDM were examined by using logistic regression model.

RESULTSThe prevalence of GDM was 14.73%. There was significant negative correlation between pregestational BMI and weight gain during the first half of pregnancy (r=-0.085, P<0.01), meanwhile the weight gain of GDM women was significantly higher than that of women without GDM. The women with pregestational overweight or obesity had increased risks of GDM. The results from the logistic regression analysis showed that the risk factors included age≥35 years (OR=3.06, 95% CI: 1.68-5.58), fasting plasma glucose level during early pregnancy (OR=2.17, 95% CI: 1.57-3.00), pregestational overweight (OR=2.08, 95% CI: 1.38-3.13), pregestational obesity (OR=3.73, 95% CI: 1.84-7.56).

CONCLUSIONPregestational overweight or obesity and body weight gain during pregnancy were associated with increased risk of GDM.