Tuesday, January 03, 2012 Study Showing No Effect of Exercise on Gestational Diabetes Raises Questions Researchers in Norway found that when they randomly assigned 855 pregnant women to either exercise 3 times a week or to regular prenatal care alone, the exercisers were no less likely to develop gestational diabetes, says an article by Reuters. All of the women in the clinical trial were in their 18-22-week range of pregnancy. Women in the exercise program took an hour-long class once a week for 12 weeks—low-impact aerobics, plus strengthening and stretching exercises. They also were given an at-home workout to do twice a week. By the third trimester, 7% of the exercise group had been diagnosed with gestational diabetes, versus 6% of the comparison group. According to Reuters, Rita W. Driggers, MD, an obstetrician and director of the maternal-fetal medicine fellowship program at Washington Hospital Center in Washington, DC, who was not involved in the study, said that the findings do not mean exercise is no help to pregnant women. She noted that only 55% of women in the exercise group actually stuck with their routine and only 13% of the women in the study were exercising at a moderate to high intensity 3 times a week when they entered the study—the level the exercisers were asked to adopt. The study's lead author said 1 possible explanation for the results is "that starting exercise in the second trimester is too late." Signe N. Stafne, PT, suggests that exercise before pregnancy and in early pregnancy could be more important, "due to the metabolic changes that occur in early pregnancy." The women in this study also were at relatively low risk for gestational diabetes because they were in the normal weight range, on average, when they entered the study. A study focused on women who are overweight and obese—who are at increased risk of gestational diabetes—might produce different results, Reuters says. Full text of this study is available in the January issue of Obstetrics & Gynecology.