Does exercise training during pregnancy affect gestational age? A randomised controlled trial

Background: Some controversy exists over the possibility that exercise during pregnancy might increase the risk of preterm delivery. Objective: This study aimed to determine the possible cause-effect relationship between regular exercise performed during the second and third trimesters of pregnancy by previously sedentary, healthy gravidae and gestational age at the moment of delivery. Methods: Caucasian (Spanish) women with singleton gestation were assigned to either a training (n = 72) or a control (n = 70) group. The supervised training programme focused mainly on very light resistance and toning exercises and included similar to 80 sessions (three times/week, 35 min/session from weeks 12-13 to weeks 38-39 of pregnancy). Results: No significant differences were found (p>0.05) between the groups in those maternal characteristics (age, smoking habits, number of hours standing or prior parity history) that could potentially influence gestational age. The mean gestational age did not differ (p = 0.745) between the training (39 weeks,3 days (SD 1 day)) and the control group (39 weeks,4 days (SD 1 day)). Conclusions: Previously sedentary, healthy gravidae with singleton gestation can safely engage in moderate, supervised exercise programmes until the end of gestation as this would not affect gestational age.