Objective: A prospective randomized controlled trial was designed to assess the benefits and possible risks of aerobic exercise during pregnancy, using a fitness regimen based on the 2002 American College of Obstetricians and Gynecologists guidelines for exercise during pregnancy.
Methods: Inactive women were randomized at 12–14 wk gestation to a group that remained sedentary or to a group that performed moderate aerobic exercise 45–60 min, 4 d·wk−1, through 36 wk gestation. Thirty-one subjects in each group completed the study.
Results: Compared with women who remained sedentary, active women improved aerobic fitness (P < 0.05) and muscular strength (P < 0.01), delivered comparable size infants with significantly fewer cesarean deliveries (P < 0.01), and recovered faster postpartum (P < 0.05), at least related to the lower incidence of cesarean section. Active women developed no gestational hypertension (P = 0.16 compared with controls) and reported no injuries related to the exercise regimen. In the active group, there was one premature birth at 33 wk by a woman with a history of premature delivery of twins at 34 wk. There were no differences between groups in the incidence of gestational diabetes, musculoskeletal pains during pregnancy, flexibility on sit-and-reach test, mean length of pregnancy, neonatal Apgar scores, placenta weights, overall length of labor, weight gain during pregnancy, or weight retention postpartum.
Conclusion: Previously sedentary women who began exercising at 12–14 wk improved fitness and delivery outcomes.