A Prospective Examination of Physical Activity Predictors in Pregnant Women with Normal Weight and Overweight/Obesity

Background: Scant research has examined the relationship between exercise behavior and weight status in pregnant women. Methods: A prospective study was conducted in which pregnant women (N = 332) completed self-report measures at each trimester. Repeated measures multivariate analysis of covariance (controlling for race, education, and parity) examined changes in the motivational determinants of exercise over time and by weight status. Regression analyses were conducted to understand how the motivational determinants predicted exercise behavior and to examine the impact of prepregnancy weight status. Results: A significant main effect for time was observed, with an increase in early pregnancy followed by a decrease in late pregnancy for the motivational determinants of exercise and exercise behavior. A significant main effect for weight status was observed such that normal weight pregnant women had significantly greater attitude and intention for exercise when compared with pregnant women with overweight/obesity. The primary predictors of intention were perceived behavioral control (first to second trimester) and attitude (second to third trimester). The primary predictor of exercise behavior was intention. Prepregnancy weight status provided no unique contributions. Conclusions: Findings from this study suggest that interventions designed to promote exercise in pregnancy should consider targeting perceived behavioral control in early pregnancy and attitude in later pregnancy. Improving exercise attitude in women with overweight or obesity may further strengthen their motivation to be active in pregnancy. Customized interventions may need to be designed to address the unique needs of women because their motivational determinants change over the course of pregnancy.