BOSTON — Pregnant women who limit sedentary time to no more than eight hours a day and increase light physical activity to at least seven hours daily may reduce their risk of developing hypertensive disorders of pregnancy by nearly 30%, according to preliminary research presented at the American Heart Association’s EPI|Lifestyle Scientific Sessions 2026.
“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 study included 470 women across three U.S. cities, who wore monitors to measure sedentary behavior, sleep and physical activity during each trimester.
High blood pressure affects up to 5%-10% of all pregnancies and is a leading cause of fetal and maternal disease and death. The research found that women who limited sitting to about eight hours, engaged in at least seven hours of light activity, 22 minutes of moderate-to-vigorous activity and nine hours of sleep had a 30% lower risk of developing conditions such as gestational hypertension or preeclampsia. The optimal daily pattern—about six hours sitting, nearly eight hours light activity, four minutes higher-intensity activity and 10 hours rest—was linked to an 8% chance of hypertensive disorders, compared to 16.9% among those with typical patterns.
“Sedentary behaviors and light physical activity were the strongest predictors of hypertensive disorders of pregnancy risk across all trimesters,” Whitaker noted. The risk rose for those who sat more than 10 hours per day or had less than five hours of light activity. The findings align with the American Heart Association’s Life Essential 8 for Pregnancy recommendations, which encourage moving throughout the day, adequate sleep and healthy habits.
Natalie A. Bello, M.D., M.P.H., an AHA volunteer expert not involved in the study, commented, “The researchers extend this to the pregnant population where nearly 20% of participants developed a hypertensive disorder of pregnancy. They saw incremental associations between more physical activity and lower risk. It remains to be seen whether this association is causal.”
The study had limitations, including a predominantly white, higher-education cohort, and the number of hypertensive cases was too small to analyze preeclampsia and gestational hypertension separately. “More research is needed to test whether helping pregnant women sit less and move more throughout the day can reduce their risk,” Whitaker said. The findings are considered preliminary until published in a peer-reviewed journal.
