Moderate-intensity physical activity in pregnancy as a strategy for the prevention of gestational diabetes mellitus: Pathophysiologic rationale and clinical evidence

Gestational diabetes mellitus (GDM) is a common metabolic complication of pregnancy associated with significant short- and long-term consequences for both maternal and offspring health. Its development reflects progressive pregnancy-related insulin resistance driven by placental hormones and metabolic adaptations, which in some women is compounded by inadequate pancreatic β-cell compensation and inflammatory activation. Moderate-intensity physical activity has been proposed as a preventive strategy because it directly targets peripheral insulin sensitivity and glucose metabolism. This review examines the pathophysiologic rationale and clinical evidence supporting moderate-intensity exercise during pregnancy as an approach to reduce GDM risk. Mechanistic data demonstrate that exercise enhances insulin-independent glucose uptake through GLUT4 translocation, improves mitochondrial efficiency, reduces pro-inflammatory cytokines, favorably alters adipokine profiles, and limits excessive gestational weight gain. Observational studies consistently report inverse associations between maternal physical activity and GDM incidence. Randomized controlled trials show more variable findings but suggest modest reductions in risk, particularly when interventions are initiated early and adequately supervised. Meta-analyses indicate relative risk reductions of approximately 20-30%, although heterogeneity in study design and adherence remains substantial. Overall, moderate-intensity exercise represents a physiologically plausible, low-risk, and moderately effective strategy for GDM prevention and should be integrated into routine prenatal care.