OBJECTIVE: To evaluate the incremental effect of weight gain above that recommended for term pregnancy (15 pounds) on postpartum weight retention at 1 year among obese women.
METHODS: In a retrospective cohort study, we identified 1,656 singleton gestations resulting in live births among obese women (body mass index at or above 30 kg/m2) between January 2000 and December 2005 in Kaiser Permanente Northwest. Pregnancy weight change (last available predelivery weight minus weight at pregnancy onset) was categorized as less than 0, 0–15, greater than 15 to 25, greater than 25 to 35, and greater than 35 pounds. Postpartum weight change (weight at 1 year postpartum minus weight at pregnancy onset) was defined as less than 0, 0–10, and greater than 10 pounds.
RESULTS: Total gestational weight gain was –33.2 (weight loss) to +98.0 pounds (weight gain). Nearly three fourths gained greater than 15 pounds, and they were younger and weighed less at baseline than women who gained 15 pounds or less. Pregnancy-related weight change showed a significant relationship with postpartum weight change. For each pound gained during pregnancy, there was a 0.4-pound increase above baseline weight at 1 year postpartum. In adjusted logistic regression models, the risk of a postpartum weight greater than 10 pounds over baseline was twofold higher for women gaining greater than 15 to 25 pounds compared with women gaining 0–15 pounds (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.54–3.10), fourfold higher for women gaining greater than 25 to 35 pounds (OR 3.91, 95% CI 2.75–5.56), and almost eightfold higher for women gaining greater than 35 pounds (OR 7.66, 95% CI 5.36–10.97).
CONCLUSION: Incremental increases in gestational weight gain beyond the current recommendation for obese women substantially increase the risk of weight retention at 1 year postpartum.
LEVEL OF EVIDENCE: II