OBJECTIVE: We studied the influence of maternal behavior on weight change from prepregnancy to 7 years postpartum.

METHODS: We used linear regression to study the independent and combined associations between self-reported behavior in pregnancy (dietary intake, leisure-time exercise, sedentary activity, smoking) and postpartum (breastfeeding duration and smoking) on weights at 6 months, 18 months, and 7 years postpartum.

RESULTS: Women's average 7-year weight gain was 2.07 kg, with 23% gaining >5 kg. Multivariable analyses suggested that women with healthier dietary intake, more leisure-time exercise, less sedentary behavior, and longer duration of breastfeeding on average gained 1.66 kg [95% confidence interval (CI): 1.40; 1.91] with a significantly reduced odds [OR 0.56 (95% CI: 0.49; 0.64)] of gaining >5 kg from prepregnancy to 7 years postpartum compared to women with none or one of these behaviors [mean gain 3.03 kg (95% CI: 2.68; 3.39)]. Women who ceased smoking had higher long-term weight gain than nonsmokers, but not smokers.

CONCLUSIONS: Adherence to healthy behaviors during pregnancy lowered long-term weight gain considerably by lowering postpartum weight retention and subsequent weight gain. Public health efforts to help mothers achieve healthy behaviors might prevent childbearing-related weight gain.