Fitness and strength decline during pregnancy and the early postpartum period, but improve by approximately 27 weeks postpartum regardless of the mother’s body mass index (BMI), according to research in the May issue of Medicine & Science in Sports & Exercise, the official journal of the American College of Sports Medicine (ACSM).
The study was designed to examine changes that occur in a woman’s body with pregnancy and to determine what role physical activity may play among pregnancy-induced changes in body composition and physiology. Because pregnancy may decondition a woman’s body, researchers measured fitness before pregnancy and postpartum in order to determine the overall effect of pregnancy on a woman’s fitness level.
The study recruited124 women, 76 of whom became pregnant during the course of the study. Each woman was assessed for body composition, physical activity, physical fitness and strength at prepregnancy (0 week gestation), 6 weeks postpartum and again at 27 weeks postpartum. Physical activity was evaluated by questionnaire, physical fitness was measured by a cycle ergometer test, and strength was assessed on leg press, leg extension, bench press, and latissimus pull-down by the one-repetition maximum (maximum amount of weight that could be lifted successfully at one time).
Pregnant women were found to have lower maximal oxygen consumption and leg strength from prepregnancy to 6 weeks postpartum. However, fitness levels and strength began to improve, with almost complete recovery by 27 weeks postpartum.
The decline in fitness and strength was seen in participants regardless of their initial BMI. Researchers found the women changed their postpartum activities to include more walking and home-based activities. The changes in intensity of these activities, and the changes in a woman’s responsibilities when becoming a parent, likely influenced the fitness levels of the participants during the postpartum period.