A study of 21,765 women participating in the Nurses Health Study II found that women who are physically active prior to pregnancy are less prone to developing gestational diabetes while pregnant. The participants, who had had at least one pregnancy between 1990 and 1998, completed questionnaires assessing the level of physical activity and inactive behavior.

After taking into consideration several factors, the researchers found that women with the highest levels of physical activity were 23% less apt to develop the condition, compared with sedentary women. Reporting in the Archives of Internal Medicine (March 13, 2006), the researchers indicated that women who walked briskly were 34% less prone to developing the condition, compared with women who walked at an easy pace.