Pregnant women may reduce their risk of developing hypertensive disorders such as gestational hypertension and preeclampsia by nearly 30% by limiting sedentary time to no more than eight hours a day and increasing light physical activity to at least seven hours daily, according to preliminary research presented at the American Heart Association’s EPI|Lifestyle Scientific Sessions 2026. The study, involving 470 women across three U.S. cities, measured sedentary behavior, sleep, and physical activity across a 7-day, 24-hour timeframe during each trimester.
“Our study suggests that in the real world, where daily routines vary widely, it may actually be the balance of sitting time and light intensity movement across the entire day that matters most,” said lead study author Kara Whitaker, Ph.D., M.P.H., FAHA, an associate professor at the University of Iowa. The findings highlight that everyday movement and limiting prolonged sitting may play a larger role than previously understood in preventing hypertensive disorders of pregnancy.
The study found that among participants, 18.6% developed hypertensive disorders of pregnancy. The lowest-risk daily activity pattern included about six hours of sitting, nearly eight hours of light physical activity, four minutes of higher-intensity exercise, and roughly 10 hours of rest. This pattern was associated with an 8% chance of developing hypertensive disorders, compared to 16.9% in those with typical activity patterns. The optimal combination reduced risk by more than half compared to typical patterns and by nearly 80% compared to the least healthy patterns.
Sedentary behavior and light physical activity were the strongest predictors of risk across all trimesters. Risk increased when women sat more than 10 hours per day or engaged in less than five hours of light activity. “These findings have the potential to shift how we think about physical activity and sleep during pregnancy,” Whitaker said. The results align with the American Heart Association’s Life Essential 8 for Pregnancy recommendations, which encourage moving throughout the day and getting adequate sleep.
Natalie A. Bello, M.D., M.P.H., an American Heart Association volunteer expert, noted that the study extends knowledge to pregnant populations, where nearly 20% developed hypertensive disorders. She emphasized that future studies are needed to test whether increasing physical activity and reducing sedentary behavior causally lowers risk. The study had limitations, including a predominantly white, higher-education sample, and the inability to analyze preeclampsia and gestational hypertension separately.
More research is required to confirm these findings and to develop quantitative guidelines for sitting and light activity during pregnancy. The study was presented as an abstract and is considered preliminary until published in a peer-reviewed journal. For more information, visit the American Heart Association newsroom.
