The role of exercise in reducing the risks of gestational diabetes mellitus.

Gestational diabetes mellitus (GDM) is the most common medical complication of pregnancy and is particularly prevalent among obese women. Both GDM and obesity confer significant comorbidities for the mother and her offspring, including perinatal complications, excessive fetal growth and long-term risks for maternal and offspring obesity and diabetes. Exercise has well-documented health benefits and reduces peripheral insulin resistance in nonpregnant individuals, a major risk factor for the development of diabetes. Observational studies conducted in large population-based cohorts suggest that women who are the most active before pregnancy are less insulin-resistant in late pregnancy and have lower rates of GDM. This article will review the evidence supporting a role for exercise in the prevention of GDM, the management of glycemic control in women with established GDM, and the reduction of GDM-associated maternal and offspring health consequences. Wherever possible, the discussion will focus on studies carried out on obese women. However, there are many areas where strong evidence is lacking in obese populations, and it may be inferred from similar studies performed in normal weight pregnant women.