“Exercise prescription for the development and maintenance of fitness in non–pregnant women consist of activities to improve cardiorespiratory (aerobic exercise) and musculoskeletal (resistive exercise) status. Exercise prescription in pregnancy should include the same elements... activities that promote musculoskeletal fitness are part of an overall exercise prescription. Typically, these include both resistance training and flexibility exercises... In one study, individually prescribed strength training of multiple muscle group was used as part of an overall conditioning program for pregnant women. Fetal heart rate were monitored during training at 28 and 38 weeks gestation, and they remained unchanged. It was concluded that relatively low weights with multiple repetitions lifted through a dynamic range of motion appear to be an effective and safe type of resistance during pregnancy exercise.”



“Doctors also were concerned that regular exercise could slow fetal growth because during pregnant workouts, blood tends to be diverted to the exercising muscles and possibly, away form the uterus. Most studies have found that pregnant exercise has no effect on birth weight, and a few studies suggested that moderate exercise may actually increase birth weight. Recent studies have found that moderate exercise in early pregnancy improves growth of the placenta.”