Gestational weight gain and postpartum weight retention in a cohort of Nova Scotian women.

Excess gestational weight gain (GWG) may predispose mothers to becoming overweight or obese. The aim of this study was to investigate the association between GWG, according to the American Institute of Medicine (IOM) guidelines, and postpartum weight retention (PPWR). A cohort of 12,875 women from Nova Scotia, Canada with at least two consecutively recorded pregnancies was identified through a population-based perinatal database between 1993 and 2010. GWG was calculated as the difference between delivery and prepregnancy weights. PPWR, analyzed as a continuous variable in linear regression models, was calculated via interpregnancy weight change. Fifty eight percent of the total study population gained in excess of the IOM guidelines. Mean PPWR, adjusted for age and prepregnancy body mass index (BMI) among women with excess GWG was 5.0 kg (95 % CI 4.9-5.2), greater than women with adequate (2.1 kg, 95 % CI 1.8-2.3) or inadequate GWG (0.3 kg, 95 % CI 0-0.7). Effect modification by prepregnancy BMI was observed; the relationship between excess GWG and increased PPWR was observed in all prepregnancy BMI categories, yet was greatest among underweight women (7.5 kg, 95 % CI 6.6-8.3). Effect modification by parity was also observed; in contrast to multiparous women, primiparous women who gained in excess of GWG guidelines retained more postpartum weight (5.3 kg, 95 % CI 5.1-5.5 vs. 4.3 kg, 95 % CI 4.0-4.7). This study demonstrates that excess GWG is associated with an increase in the amount of weight retained after pregnancy. Interventions targeted to promote optimal GWG are warranted.