Regular Exercise to Prevent the Recurrence of Gestational Diabetes Mellitus: A Randomized Controlled Trial

OBJECTIVE:To investigate the effect of a supervised home-based exercise program on the recurrence and severity of gestational diabetes mellitus (GDM) together with other aspects of maternal health and obstetric and neonatal outcomes.METHODS:This randomized controlled trial allocated women with a history of GDM to an exercise intervention (14-week supervised home-based stationary cycling program) or to a control group (standard care) at 131 weeks of gestation. The primary outcome was a diagnosis of GDM. Secondary outcomes included maternal fitness, psychological well-being, and obstetric and neonatal outcomes. A sample size of 180 (90 in each group) was required to attain 80% power to detect a 40% reduction in the incidence of GDM.RESULTS:Between June 2011 and July 2014, 205 women provided written consent and completed baseline assessments. Of these, 33 (16%) were subsequently excluded as a result of an elevated baseline oral glucose tolerance test (OGTT), leaving 172 randomized to exercise (n=85) or control (n=87). Three women miscarried before the assessment of outcome measures (control=2; exercise=1). All remaining women completed the postintervention OGTT. The recurrence rate of GDM was similar between groups (control 40% [n=34]; exercise 40.5% [n=34]; P=.95) and the severity of GDM at diagnosis was unaffected by the exercise program with similar glucose and insulin responses to the OGTT (glucose 2 hours post-OGTT 7.71.5 compared with 7.6 +/- 1.6 mmol/L; P>.05). Maternal fitness was improved by the exercise program (P<.01) and psychological distress was reduced (P=.02). There were no differences in obstetric and neonatal outcomes between groups (P>.05).CONCLUSION:Supervised home-based exercise started at 14 weeks of gestation did not prevent the recurrence of GDM; however, it was associated with important benefits for maternal fitness and psychological well-being.CLINICAL TRIAL REGISTRATION:ClinicalTrials.gov, https://clinicaltrials.gov, NCT01283854.