The prevalence of obesity in the US has increased markedly in women in their reproductive years over the past 3 decades, partially due to higher rates of postpartum weight retention. This was a prospective cohort study that investigated mode of delivery as an independent risk factor for postpartum weight retention at 1 year postpartum.

Data from 2500 first-time mothers, aged 18–35 with singleton pregnancies were included in this analysis. Postpartum weight retention was measured at 1 year after delivery and was defined as weight at 1 year compared to weight just before becoming pregnant. Logistic regression models assessed the association between mode of first delivery and subsequent weight retention of 10 pounds or more, adjusting for key confounders including pre-pregnancy body mass index, gestational weight gain, age, education, poverty status, smoking, race/ethnicity, gestational age, pregnancy complications, breastfeeding and exercise habits during pregnancy and in the first year after delivery.

At 12 months after delivery the women who had delivered by cesarean were more likely to have a postpartum weight retention of 10 pounds or more (27.9%), than those who had delivered vaginally (22.2%), unadjusted OR 1.35 (95% CI 1.11–1.65, p=.003). Even after controlling for confounding variables, mode of delivery remained significantly associated with postpartum weight retention of 10 pounds or more, adjusted OR 1.30 (95% CI 1.04–1.62, p=.02).

Cesarean delivery at first childbirth is associated with increased risk of weight retention of 10 pounds or more at 1 year postpartum.