The Effect of an Exercise Intervention on Gestational Weight Gain: The Behaviors Affecting Baby and You (B.A.B.Y.) Study: A Randomized Controlled Trial.

Purpose: To examine the effect of a prenatal exercise intervention on gestational weight gain (GWG) and to update meta-analyses.

Design: Randomized controlled trial and meta-analysis.

Setting: Obstetrical practices in a Western Massachusetts hospital.

Patients: We analyzed 241 ethnically diverse pregnant participants at high risk for gestational diabetes in the Behaviors Affecting Baby and You (B.A.B.Y.) study. A total of 118 participants were randomized to an exercise intervention group and 123 to a comparison health and wellness intervention group.

Intervention: A 12-week individually tailored, motivationally matched program designed to increase the compliance with guidelines for exercise during pregnancy (30 min/day).

Measures: The GWG and compliance with 2009 Institute of Medicine (IOM) guidelines for GWG abstracted from medical records.

Analysis: Unadjusted logistic regression, intent-to-treat. Results were added to the existing meta-analyses using a random effects model.

Results: Women randomized to the exercise group had a lower mean GWG than the comparison group (-0.97 kg, P value = .39) and were less likely to exceed IOM guidelines (odds ratio = 0.69, 95% confidence interval [CI] 0.34-1.40), but results were not statistically significant. Meta-analyses yielded a -0.63 kg (95% CI -1.17 to -0.08, P = .02) reduction in GWG and a 20% reduction in odds of exceeding IOM guidelines (95% CI 0.73 to 0.89) for the exercise intervention.

Conclusion: Findings from this randomized trial among ethnically diverse women contribute to the results of meta-analyses supporting exercise as a means of attenuating GWG.