Association of prenatal physical activity and gestational weight gain: Results from the first baby study

Background: In response to increasing rates of excessive gestational weight gain (GWG) and evidence of postpartum weight retention and long-term overweight and obesity, the Institute of Medicine (IOM) revised their guidelines for GWG in 2009. Prenatal physical activity is recommended, although its role in preventing excessive GWG is unclear. We sought to understand the association between prenatal physical activity and GWG in a longitudinal cohort. Methods: During a baseline survey at 34weeks, women (n = 3,006) reported their height, prepregnancy weight, and physical activity during pregnancy. GWG was self-reported at 1-month postpartum. Multivariable logistic regression adjusting for age, race/ethnicity, education, poverty status, marital status, gestational age at the time of delivery, and smoking was used to model the association between adequate physical activity during pregnancy and exceeding the IOM recommendations for GWG. Findings: Overweight women were most likely to exceed the IOM recommendations for GWG (78.7%), followed by obese women and normal weight women (65.0% and 42.4%, respectively). The majority of women participated in some physical activity during pregnancy, with 41.2% engaging in 60 to 149minutes and 32.1% engaging in at least 150minutes of physical activity per week. In adjusted analysis, meeting the physical activity guidelines was associated with a 29% (confidence interval, 0.57-0.88) lower odds of exceeding the IOM recommendations for GWG compared with inactive women. Conclusions: Findings of high rates of excessive GWG, especially among women with overweight and obesity, are concerning given the associated health burdens. The association of guideline-concordant physical activity with appropriate GWG suggests this is an important target for future interventions.