Impact of an exercise intervention on physical activity during pregnancy: the behaviors affecting baby and you study.

Objectives: We examined the impact of a prenatal exercise intervention on physical activity in 260 women at risk for gestational diabetes mellitus.

Methods: We randomized participants in the Behaviors Affecting Baby and You (BABY) Study, which took place from 2007 to 2012, to either a 12-week individually tailored, motivationally matched exercise intervention (n=132) or to a comparison health and wellness intervention (n=128). We assessed physical activity with the Pregnancy Physical Activity Questionnaire. We used linear mixed models to evaluate the impact of the interventions on change in physical activity according to intensity and type, total walking, and sedentary behavior.

Results: Compared with the health and wellness arm, the exercise arm had significantly greater increases in sports or exercise activity (0.3 vs 5.3 metabolic equivalent of task [MET] hours/week; P<.001), and smaller declines in total activity (-42.7 vs -2.1 MET hours/week; P=.02) and activities of moderate to vigorous intensity (-30.6 vs -10.6 MET hours/week; P=.05), and was more likely to achieve recommended guidelines for physical activity (odds ratio=2.12; 95% confidence interval=1.45, 3.10).

Conclusions: These findings extend the previous literature by demonstrating the benefits of a clinically feasible exercise intervention in an ethnically and socio-economically diverse population. Given the increased risk of adverse maternal health outcomes in ethnic minority groups, these findings may have important implications for reducing health disparities.