The power of believing: Salient belief predictors of exercise behavior in normal weight, overweight, and obese pregnant women

Background: Nearly 50% of U.S. women enter pregnancy as overweight or obese (OW/OB). There is a critical need to understand how to motivate OW/OB pregnant women for exercise behavior to improve their health and reduce adverse pregnancy outcomes. Purpose: To examine salient Theory of Planned Behavior belief predictors of normal weight (NW) and OW/OB pregnant women's exercise behavior (EXB) across pregnancy. Methods: Pregnant women (N = 357) self-reported their exercise beliefs and behavior during each pregnancy trimester. Pearson correlations were used to examine exercise beliefs-behavior associations. Stepwise regressions were used to identify trimester (TRI) 1 and TRI 2 belief predictors of TRI 2 and TRI 3 EXB, respectively, for each weight status group. Belief endorsement was examined to identify critical beliefs. Results: TRI 1 EXB beliefs explained 58% of the total variance (22% NW, 36% OW/OB) in TRI 2 EXB. TRI 2 EXB beliefs explained 32% of the total variance (17% NW, 15% OW/OB) in TRI 3 EXB. Individual beliefs varied by weight status and trimester. Control beliefs emerged with the lowest endorsement; making them most critical to target for exercise interventions. Conclusion: Prenatal exercise interventions should be weight status specific and target salient beliefs/barriers unique to the pregnancy trimesters.