Pregnant women who develop gestational diabetes usually do so during their 24th week of pregnancy, reported the American Diabetes Association (ADA). It’s one of the most frequent complications of pregnancy, in addition to excessive weight gain — both of which may be avoided with moderate exercise.

This idea comes from a newly published study in the BJOG: an International Journal of Obstetrics and Gynaecology; researchers systematically reviews more than 2,800 healthy pregnant women enrolled in exercise programs. Prior to these programs, women were getting little to no exercise. And after enrollment, they were getting moderate amounts.

Researchers found women working out reduced the risk of gestational diabetes by more than 30 percent; women exercising throughout their entire pregnancy reduced their risk by 36 percent. Enrolled women, too, were an average two pounds lighter, especially if they started exercising during the second trimester of pregnancy. These effects were even greater when women combined toning, strength, flexibility, and aerobic exercise.

“Exercise is not something to be feared during pregnancy,” Gema Sanabria- Martinez, from Virgen de la Luz Hospital, lead author of the study, said in a press release. “The moderate levels of exercise used in these studies had significantly positive effects on health and were found to be safe for both mother and baby."

Reducing risk for gestational diabetes also reduces mothers' risk for other disorders, such as pre-eclampsia, hypertension, and preterm birth. Children born to mothers without this type of diabetes are less likely to be overweight or obese, and are at lower risk for developing diabetes themselves.

Many women are hesitant to exercise during pregnancy for fear of hurting themselves and their baby. It doesn't help exercise recommendations are outdated, Dr. James Pivarnik, president of the American College of Sports Medicine foundation, told Parents.

"Physicians aren't trained to counsel pregnant women about exercise," Pivarnik added. "It's a rare bird who keeps up with the exercise and pregnancy literature...If a woman is having a normal pregnancy, she can continue to exercise, and the upper limit of the level can be reasonably close to what she was doing before pregnancy." Medical Daily previously outlined safety tips for active pregnant women, here.

Mike Marsh, deputy editor-in-chief of BJOG, said the present study’s “shows a beneficial effect of exercise on healthy pregnant women who ordinarily did little or no exercise.” It’s possible this may influence future exercise recommendations for pregnant women. But since the study did look at already healthy women, future research should include pregnant women following various lifestyles in order to measure moderate exercise’s true effects.

Source: Sanabria-Martínez G, García-Hermoso A, Poyatos-León R, et al. Effectiveness of physical activity interventions on preventing gestational diabetes mellitus and excessive maternal weight gain: a meta-analysis. BJOG: An International Journal of Obstetrics & Gynaecology, 2015.