A large multicenter cohort study published in JAMA suggests that reducing sedentary time and increasing light daily movement during pregnancy may significantly lower the risk of adverse pregnancy outcomes. The findings provide new evidence that simple lifestyle changes such as standing more frequently, walking regularly, and minimizing prolonged sitting may contribute to healthier pregnancies.
Adverse pregnancy outcomes, including hypertensive disorders of pregnancy (HDP), gestational diabetes (GD), preterm birth, and small-for-gestational-age (SGA) infants, affect nearly one in five pregnancies worldwide. These complications are associated with long-term cardiovascular and metabolic risks for both mother and child. Although moderate-to-vigorous physical activity is already recommended during pregnancy, limited evidence has been available regarding the impact of lighter daily activities such as standing, slow walking, or reducing sedentary behavior.
The Pregnancy 24/7 study, conducted between 2021 and 2025 across medical centers in Iowa, Pennsylvania, and West Virginia, enrolled 470 pregnant individuals before 13 weeks of gestation. Researchers used thigh-worn accelerometers to continuously monitor movement patterns throughout pregnancy, allowing precise assessment of sedentary time, light-intensity physical activity, and daily step counts across all three trimesters.
Participants spent an average of 10 hours per day in sedentary behavior, engaged in approximately 4.6 hours of light-intensity activity, and accumulated nearly 6,783 steps daily. Overall, 37% of participants experienced at least one adverse pregnancy outcome, while hypertensive disorders occurred in 18.3% of pregnancies. Investigators identified a strong association between prolonged sedentary behavior and increased pregnancy complications. Pregnant individuals who remained sedentary for approximately 10 or more hours daily had more than double the risk of adverse pregnancy outcomes compared with those averaging about 7 hours of sedentary time per day. Extended sitting periods lasting 60 minutes or longer appeared particularly unfavorable.
Conversely, higher levels of light-intensity physical activity were linked to substantially lower risks of complications. Participants engaging in nearly 7 hours of light movement daily demonstrated almost half the risk of adverse pregnancy outcomes compared with individuals averaging only 3 hours per day. Standing activities, rather than walking alone, appeared to show especially favorable associations with reduced hypertensive disorders of pregnancy. Daily step counts also demonstrated measurable benefits. Women achieving approximately 6,000 to 9,000 steps per day experienced lower risks of adverse outcomes compared with those averaging fewer than 3,918 steps daily. Importantly, these associations remained significant even after adjusting for moderate-to-vigorous exercise levels and prepregnancy body mass index.
The findings support the growing public health message encouraging pregnant individuals to “sit less and move more.” Researchers emphasized that the health benefits observed in the study extended beyond structured exercise programs and could potentially be achieved through simple, practical increases in everyday movement.
The earlier Monitoring Movement and Health (MoM Health) study by Barone Gibbs and colleagues similarly explored sedentary behavior and physical activity during pregnancy using device-based monitoring. Both studies highlighted that prolonged sedentary time and reduced activity may negatively influence maternal and pregnancy outcomes, whereas greater daily movement and light-intensity activity may offer protective effects. Together, these findings reinforce the clinical importance of movement behaviors throughout pregnancy and support the development of targeted interventions aimed at improving maternal and fetal health.
Researchers noted that the study does not replace existing exercise recommendations but broadens the understanding of how overall daily movement patterns may influence pregnancy health. However, they acknowledged several limitations. As an observational study, the findings cannot establish direct causation. In addition, the participant population lacked substantial racial and ethnic diversity, and the relatively small number of certain complications, including gestational diabetes and preterm birth, limited subgroup analyses.
The authors concluded that reducing sedentary behavior and encouraging light daily movement may represent a practical, low-cost strategy to improve maternal and fetal outcomes. They called for future randomized clinical trials to determine whether targeted “sit less, move more” interventions can directly reduce pregnancy-related complications and improve long-term maternal cardiovascular health.
References
- Barone Gibbs B, Kim J, Gallagher J, Jones MA, Crisp AH, Wilhite K, et al. Adverse pregnancy outcomes and sedentary behavior, light-intensity physical activity, and daily steps. JAMA. Published online May 27, 2026.
- Barone Gibbs B, Jones MA, Jakicic JM, Jeyabalan A, Whitaker KM, Catov JM. Objectively Measured Sedentary Behavior and Physical Activity Across 3 Trimesters of Pregnancy: The Monitoring Movement and Health Study. J Phys Act Health. 2021 Mar 1;18(3):254-261.