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/m) 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.