Postpartum Weight Retention in Primiparous Women and Weight Outcomes in Their Offspring

Introduction: To explore the effect of prepregnancy body mass index (BMI) and gestational weight gain on postpartum weight retention in nulliparous women and weight-for-length percentiles of offspring to 2 years following birth. Methods: A retrospective secondary analysis of a large, prospective longitudinal study of women conducted during pregnancy and after their first birth was completed to examine outcomes associated with postpartum weight retention. A chart review of the offspring of these women was completed to explore the relationship between maternal prepregnancy BMI and gestational weight gain on offspring weight-for-length percentiles. Results: Data from 652 woman-infant dyads were available for analysis. Average postpartum weight retention was 4.0 kg at one year for all groups. At 6 weeks postpartum, women who were obese prior to pregnancy retained significantly less weight than did women who were normal weight prior to pregnancy (P <.05). Women who were normal weight or overweight at the onset of pregnancy and had gestational weight gain within Institute of Medicine recommendations retained significantly less weight at 6 weeks, 6 months, and 1 year postpartum (P <.01) when compared with women in those same weight groups who had a gestational weight gain in excess of the recommended guideline. Women who entered pregnancy obese and who had a gestational weight gain within the recommended weight range during pregnancy retained significantly less weight compared with women who were obese and who gained in excess of the guideline at 6 weeks postpartum only (P <.05). No statistically significant differences were seen in offspring weight-for-length percentiles at any time point based on maternal prepregnancy BMI or weight gain within guidelines. Discussion: Many women retained weight up to one year postpartum. In this study, we saw no statistically significant differences between the prepregnant BMI groups or between gestational weight gain within guidelines or in excess of guidelines on offspring weight-for-length percentiles.