Predictors of Change in Physical Activity During and After Pregnancy. Project Viva

Background: Few studies document longitudinal changes in physical activity from prepregnancy to the postpartum period. Methods: This study estimated change in self-reported leisure-time physical activity in 1442 women before pregnancy, during the second trimester, and at 6 months postpartum. In addition, it also examined predictors of becoming insufficiently active during or after pregnancy. Results: The mean (SD) age was 32.5 (4.5) years, 34% of the women were overweight or obese prepregnancy (body mass index equal to or greater than 25 kg/m²), and 76% were white. Before pregnancy, the mean total leisure physical activity was 9.6 hours per week. The reported decrease in total activity between prepregnancy and 6 months postpartum was -1.4 (95% CI=-1.0 to -1.9) hours per week, accounted for by decreases in moderate and vigorous physical activity but not walking. Prevalence of insufficiently active lifestyle (less than 150 minutes per week of total activity) increased from 12.6% before pregnancy to 21.7% during the postpartum period. The OR for becoming insufficiently active during pregnancy was 1.58 (95% CI=1.07-2.32) in women with at least one child compared with no children. Predictors of becoming insufficiently active postpartum included postpartum weight retention (OR=1.31; 95% CI=1.05-1.58 for each 5-kg increment); working longer hours in the first trimester (e.g., OR=5.12; 95% CI=1.96-13.4 for 45+ vs 0 hours); and reporting that lack of child care was a barrier to physical activity (OR=1.73; 95% CI=0.99-3.02). Conclusions: Women reported decreases in moderate and vigorous physical activity during pregnancy that persisted at 6 months postpartum. Levels of walking did not decline. Children in the home, longer work hours, and lack of child care were predictors of becoming insufficiently active during or after pregnancy.