Physical Activity Interventions in Pregnancy and Risk of Gestational Diabetes Mellitus A Systematic Review and Meta-analysis

OBJECTIVE: Gestational diabetes mellitus (GDM) is a common complication of pregnancy associated with an increased incidence of pregnancy complications, adverse pregnancy outcomes, and maternal and fetal risks of chronic health conditions later in life. Physical activity has been proposed to reduce the risk of GDM and is supported by observational studies, but experimental research assessing its effectiveness is limited and conflicting. We aimed to use meta-analysis to synthesize existing randomized controlled studies of physical activity and GDM. DATA SOURCES: We searched MEDLINE, Cochrane Central Register of Controlled Trials, and ClinicalTrials. gov for eligible studies. METHODS OF STUDY SELECTION: The following combination of keywords was used: (pregnant or pregnancy or gestation or gestate or gestational or maternity or maternal or prenatal) AND (exercise or locomotion or activity or training or sports) AND (diabetes or insulin sensitivity or glucose tolerance) AND (random* or trial). Eligibility was restricted to studies that randomized participants to an exercise-only-based intervention (ie, separate from dietary interventions) and presented data regarding GDM risk. Two authors performed the database search, assessment of eligibility, and abstraction of data from included studies, and a third resolved any discrepancies. A total of 469 studies was retrieved, of which 10 met inclusion criteria and could be used for analysis (3,401 participants). TABULATION, INTEGRATION, AND RESULTS: Fixed-effects models were used to estimate summary relative risk (RR) and 95% confidence interval (CI) and I-2 to assess heterogeneity. There was a 28% reduced risk (95% CI 9-42%) in the intervention group compared with the control group (RR 0.72, P=.005). Heterogeneity was low (I-2=12%) and nonsignificant (P=.33). CONCLUSION: The results from this meta-analysis suggest that physical activity in pregnancy provides a slight protective effect against the development of GDM. Studies evaluating type, timing, duration, and compliance of physical activity regimens are warranted to best inform obstetric guidelines.