Associations of prepregnancy body mass index and gestational weight gain with pregnancy outcomes in nulliparous women delivering single live babies

The study was to assess the associations of prepregnancy body mass index (BMI) and gestational weight gain (GWG) with pregnancy outcomes. This was a retrospective analysis of 2973 nulliparous women who delivered single live babies. Prepregnancy BMI was categorized as underweight (<18.5 kg/m2), normal weight (18.5–24.9 kg/m2) or overweight/obese (≥25.0 kg/m2). GWG was categorized as inadequate, adequate or excessive. 567 (19.1%) women were overweight/obese and 1600 (53.8%) exhibited excessive GWG. Compared with women of normal weight, overweight/obese women had a higher incidence of cesarean section (odds ratio, 95% confidence interval: 2.02, 1.59–2.56), postpartum hemorrhage (1.50, 1.05–2.14), preterm delivery (2.51, 1.83–3.45), preterm premature rupture of membranes (2.11, 1.32–3.38), gestational diabetes mellitus (2.04, 1.65–2.53), gestational hypertension (7.68, 4.21–14.00), preeclampsia (1.98, 1.18–3.33) and small for gestational age (2.81, 1.21–6.54). Compared with adequate GWG, excessive GWG increased the incidence of cesarean section (2.02, 1.59–2.56), preterm delivery (1.48, 1.05–2.71), preeclampsia (1.78, 1.34–4.27) and macrosomia (2.61, 1.61–4.25) and reduced the incidence of gestational diabetes mellitus (0.75, 0.62–0.92). High prepregnancy BMI and excessive GWG in nulliparous Chinese women are associated with adverse pregnancy outcomes. Weight control before and during pregnancy could reduce the complications of pregnancy.