This study sought to assess the effect and safety of moderate-to-vigorous resistance exercise during pregnancy. The intervention was administered during gestational weeks 14-25. The intervention group received supervised resistance exercise twice a week, performed at an activity level equivalent to within moderate-to-vigorous (n=51). The control group received generalized exercise recommendation, a home-based training program and a telephone follow up (n=41). Functional status deteriorated during the intervention in both groups and pain increased. Significant differences between the groups were obtained only for birthweight. Newborns delivered by women who underwent resistance exercise during pregnancy were significantly heavier than those born to control women; 3561 (±452) g vs. 3251 (±437)g (p=0.02), a difference that disappeared when adjustment was made for gestational age (p=0.059). Both groups showed normal health-related quality of life, blood pressure, and perinatal data.
These findings suggest that supervised, moderate-to-vigorous resistance exercise does not jeopardize the health status of healthy pregnant women or the fetus during pregnancy, but instead seems to be an appropriate form of exercise in healthy pregnancy.