A Medically Supervised Pregnancy Exercise Intervention in Obese Women: A Randomized Controlled Trial

OBJECTIVE: To evaluate whether an intensive, medically supervised exercise intervention improved maternal glycemia and gestational weight gain in obese pregnant women when compared with routine prenatal care. METHODS: This randomized controlled trial compared a medically supervised exercise intervention with routine prenatal care. The primary outcome was a reduction in mean maternal fasting plasma glucose in the intervention group by 6.9 mg/dL at the time of a 75-g oral glucose tolerance test at 24-28 weeks of gestation. Secondary outcomes included excessive gestational weight gain. The intervention consisted of 50-60 minutes of exercise: warm-up, resistance or weights, aerobic exercises, and cool-down. All women received routine prenatal care. Power calculation determined that 24 women were required per group to detect a difference of 6.9 mg/dL in fasting plasma glucose between groups based on an independent-sample t test for statistical power of 80% at a type I error rate of 0.05. A sample size of 44 per group was planned to allow a dropout rate of 33%. RESULTS: From November 2013 through August 2015, 88 women were randomized: 44 each to the exercise and control groups. Eight women in the control group and 11 in the intervention group did not complete the trial at 6 weeks postpartum (P=.61), but 43 in each group attended the 24- to 28-week glucose screen. There were no baseline maternal differences between groups. Classes commenced at a mean of 13 4/7+/-1 2/7 weeks of gestation. In early pregnancy, 51.1% (n=45/88) had an elevated fasting plasma glucose (92-125 mg/dL). There was no difference in the mean fasting plasma glucose at 24-28 weeks of gestation: 90.0+/-9.0 mg/dL (n=43) compared with 93.6+/-7.2 mg/dL (n=43) (P=.13) or in the incidence of gestational diabetes mellitus at 24-28 weeks of gestation: 48.8% (n=21/43) compared with 58.1% (n=25/43) (P=.51) in the control and exercise groups, respectively. At 36 weeks of gestation, excessive gestational weight gain greater than 9.1 kg was lower in the exercise group, 23.5% compared with 45.2% in the control group (P