Exercise Benefits for Gestational Diabetes

 Gestational diabetes mellitus (GDM), which is maternal hyperglycemia that arises primarily during the third trimester of pregnancy, is usually diagnosed at 24 to 28 weeks of gestation with an oral glucose challenge.

Women who have risk factors for gestational diabetes, however, may have this test earlier in the pregnancy. Using new diagnostic criteria, it is estimated that gestational diabetes affects 18% of pregnancies¹.

Physical activity performed during pregnancy benefits a woman’s overall health. Instead of detraining, pregnant women undertaking moderate-intensity physical activity can maintain or increase their cardiorespiratory fitness². Furthermore, maternal exercise during pregnancy does not increase the risk of low birth weight, preterm delivery, or early pregnancy loss. On the contrary, regular exercise participation likely reduces the risk of pregnancy complications, such as preeclampsia and GDM, and shortens the duration of active labor^3,4.

Physical activity during pregnancy may prevent both GDM and possibly later-onset T2D, and engaging in regular physical activity before pregnancy frequently has been associated with a reduced risk of developing GDM. In a recent clinical trial, a moderate physical activity program performed thrice weekly during pregnancy was found to improve levels of maternal glucose tolerance in healthy, pregnant women⁵ and higher levels of physical activity participation before pregnancy or in early pregnancy significantly lower the risk of developing GDM⁶.

Similarly a recent meta-analysis reported that pregnant women with GDM who exercised on a cycle or arm ergometer or performed resistance training three times a week for 20–45 min experienced better glycemic control, lower fasting and postprandial glucose levels, and improved cardiorespiratory fitness². The same number of exercising women was prescribed insulin to control their blood sugars compared with sedentary women, however, and pregnancy outcomes were unchanged.

Compared with less vigorous activities, exercise intensity that reaches at least 60% of heart rate reserve (HRR) during pregnancy while gradually increasing physical activity energy expenditure reduces the risk of developing GDM⁷. The more vigorous the exercise, the less total exercise time is required. Thus, the general consensus is that higher levels of moderate physical activity (aerobic or resistance training) may reduce the risk of developing GDM during pregnancy and lower blood glucose levels in women who do develop it. Prevention of glucose tolerance during pregnancy may be possible, however, if women of reproductive age engage in leisure time physical activity in advance of becoming pregnant⁸.

In summary, women at high risk for GDM may be able to prevent it with lifestyle management during pregnancy. In those who develop GDM, dietary improvements and regular physical activity are frequently sufficient to manage hyperglycemia, although insulin and oral medications may be used when these changes are not enough. Management of blood glucose levels ensures better pregnancy outcomes and improves the health of both the mother and the fetus. Engaging in 30 min of moderate intensity physical activity on most, if not all, days of the week has been adopted as a recommendation for all pregnant women.

In addition, anyone wishing to earn free CME credits through the ADA for completing a new self-assessment program on exercise and diabetes may do so now through the ADA’s web site at http://professional.diabetes.org/ce.