The effect of an exercise program on maternal health and birth Outcomes in sedentary pregnant participants with obesity: Randomized controlled trial

Authors: HOLMES, CLIFTON - University Arkansas For Medical Sciences (UAMS); DINIZ-SOUSA, FLORENCIO - University Arkansas For Medical Sciences (UAMS); SIMS, CLARK - University Arkansas For Medical Sciences (UAMS); JANSEN, LISA - University Arkansas For Medical Sciences (UAMS); MARTINEZ, AUDREY - Arkansas Children'S Nutrition Research Center (ACNC); DUPENS, ALVIN - Arkansas Children'S Nutrition Research Center (ACNC); TURNER, DONALD - Arkansas Children'S Nutrition Research Center (ACNC); EDWARDS, TIM - Arkansas Children'S Nutrition Research Center (ACNC); BELLANDO, JAYNE - University Arkansas For Medical Sciences (UAMS); MASSEY-SWINDLE, TAREN - University Arkansas For Medical Sciences (UAMS); DIAZ, EVA - University Arkansas For Medical Sciences (UAMS); BORSHEIM, ELISABET - University Arkansas For Medical Sciences (UAMS); ANDRES, ALINE - University Arkansas For Medical Sciences (UAMS)

Submitted to: American College of Sports Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2025
Publication Date: 10/3/2025
Citation: Holmes, C., Diniz-Sousa, F., Sims, C.R., Jansen, L.T., Martinez, A., Dupens, A., Turner, D., Edwards, T., Bellando, J., Massey-Swindle, T., Diaz, E., Borsheim, E., Andres, A. 2025. The effect of an exercise program on maternal health and birth Outcomes in sedentary pregnant participants with obesity: Randomized controlled trial. American College of Sports Medicine. 58(3):p 559-571. https://DOI.org/10.1249/MSS.0000000000003888.
DOI: https://doi.org/10.1249/MSS.0000000000003888

Interpretive Summary: Many women begin pregnancy with obesity and low activity levels, which increases their risk for complications and long-term health problems — yet it is unclear whether exercise during pregnancy is safe or helpful. In a large clinical study of 264 pregnant women who were previously sedentary conducted at the Arkansas Children's Nutrition Center, researchers tested a supervised program that combined walking, strength training, and stretching three times per week from early pregnancy through delivery. The results showed that regular exercise was safe and significantly improved heart and lung fitness, helping women stay stronger and more physically capable throughout pregnancy. While exercise did not change pregnancy weight gain or birth outcomes in this study, it meaningfully improved physical fitness — a powerful marker of long-term health that lowers future risk for heart disease, diabetes, and complications in later pregnancies. These findings demonstrates that structured exercise during pregnancy is not only safe for women with obesity — it is a proactive investment in lifelong health for mothers.

Technical Abstract: Purpose: This study investigated the effects of a combined aerobic and resistance exercise program on maternal health and birth outcomes in pregnant people with obesity and prior sedentary lifestyle. Methods: Two hundred sixty-four pregnant people (=30.0kg/m2 ) were randomly allocated to a standard-of-care group (SOC; n = 107) or an exercise group (n = 157). The intervention consisted of aerobic, resistance, and stretching exercises, 3× per week from the 12wk of gestation until delivery. A submaximal cardiopulmonary exercise treadmill test was performed at 12 and 24wk of pregnancy. Biological sample collection, body composition assessment, resting and activity energy expenditure assessment, and depression and stress evaluations were obtained at 12.1±0.5, 24.2±0.7, and 36.0±0.5wk of gestation. Linear mixed-effect models were used to compare maternal outcomes, while linear and logistic models were used to compare delivery outcomes. Results: The median compliance for exercise sessions attended from the start of exercise (14.0±0.8wk gestation) to delivery (38.8±1.7wk gestation) was 61.7%. No significant time × group interactions were found for most maternal outcomes, however, significant time × group interactions were observed in cardiorespiratory fitness outcomes, specifically in grade (P < 0.001), heart rate (P = 0.003), workload (P < 0.001), VO' 2 (P < 0.001) during final fitness testing stage corresponding to rating of perceived exertion of 15, and oxygen uptake efficiency slope (P < 0.001). No significant effects were observed for other maternal health outcome measures, including gestational weight gain, systemic inflammation, and birth outcomes. Conclusions: Regular physical activity and participation in aerobic and resistance exercise during pregnancy are safe and effective for improving and maintaining physical fitness and activity levels in people with obesity who were previously sedentary.