Effects of Gestational Weight Gain and Physical Activity on Postpregnancy Weight Gain and Body Composition

Abstract

Retaining weight gained during pregnancy is a risk factor for a woman becoming overweight, obese, and/or increasing body fatness later in life. Pregnancy weight gain has been found to be directly related to weight retention several years following delivery. However, less is known about whether physical activity may affect postpartum weight retention or maternal body composition. PURPOSE: The purpose of this study was to examine the relationship of pregnancy weight gain, postpartum and current physical activity, to maternal body weight change over the past six years, and current body fatness. METHODS: Daily leisure time physical activity was quantified in 56 women (31 were available for this follow-up study) at 20 and 32 weeks gestation and 12 weeks postpartum. Weight gain during pregnancy was calculated by subtracting women's self-reported prepregnancy weight from body weight measured in our laboratory at approximately 32 weeks gestation. Bioelectrical Impedance Analysis was used to assess current fat free mass. Percent body fat was calculated using fat free mass and measured weight. A Modifiable Activity Questionnaire was used to assess 12 week postpartum and current physical activity levels in kcal/day/kg. Stepwise regression was used to predict weight change and current % body fat using pregnancy weight gain, physical activity at 12 weeks postpartum, and current physical activity levels as predictor variables. RESULTS: On average, the women's body weights increased 2.8 (±5.1) kg in the six years following pregnancy, with current fatness levels averaging 32±9 %. Change in body weight in the past six years was related most strongly to weight gain during pregnancy (r2=0.20), with current physical activity adding to the prediction model (final r2=0.27). In contrast, current % body fat was most strongly predicted by postpartum physical activity (r2=0.20), although pregnancy weight gain accounted for 14% additional variance (final r2=0.34) in fatness. CONCLUSIONS: Although weight gained during pregnancy was found to be more influential on long term body weight change compared to exercise performed after delivery, initiating a program of regular physical activity during the postpartum period appears to have a greater effect on body composition.