Physical activity may reduce hypertension risk in pregnancy

More light activity and less sitting in pregnancy may cut the risk of high blood pressure conditions by nearly 30 per cent, early research suggests.

The study looked at nearly 500 pregnant women at three healthcare centres in the US and found that time spent sitting and doing light physical activity were the strongest predictors of hypertensive disorders of pregnancy.

Hypertensive disorders of pregnancy include gestational hypertension and preeclampsia, a serious condition involving high blood pressure that can damage organs.

Women who limited sedentary time to about eight hours a day and did at least seven hours of light physical activity, alongside an average of 22 minutes of higher-intensity activity and nine hours of sleep, had a 30 per cent lower risk of developing these conditions.

The findings were presented at the American Heart Association’s EPI|Lifestyle Scientific Sessions 2026 in Boston and are considered preliminary.

The study, led by researchers at the University of Iowa, included 470 women aged 18 to 45 who were enrolled between 2021 and 2024 at healthcare centres in Iowa, Pennsylvania and West Virginia.

Participants wore two monitors for 24 hours over seven consecutive days during each trimester to measure sedentary behaviour, sleep and activity patterns.

Of the participants, 18.6 per cent developed hypertensive disorders of pregnancy. The lowest-risk daily pattern was linked to an 8 per cent chance of developing these conditions, compared with 16.9 per cent among those with a typical daily pattern.

The risk was higher among those who sat for more than 10 hours a day or did less than five hours of light activity daily.

Lead study author Kara Whitaker, associate professor in the department of health, sport and human physiology at the University of Iowa, said: “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.”

“This doesn’t mean exercise isn’t beneficial, rather, that when it comes to hypertensive disorders of pregnancy, everyday movement and limiting long periods of sitting may play a bigger role than we previously understood.”

She added: “These findings have the potential to shift how we think about physical activity and sleep during pregnancy. Right now, there are no clear, quantitative guidelines for how much sitting or light intensity movement is healthiest during pregnancy, and our results provide early evidence that could help shape those recommendations in the future. Ultimately, this line of research could give patients and clinicians more practical, achievable ways to support healthier pregnancies.”

Natalie A. Bello, associate professor of cardiology at the Smidt Heart Institute at Cedars-Sinai Medical Center, who was not involved in the study, said: “The researchers extend this to the pregnant population where nearly 20 per cent of participants developed a hypertensive disorder of pregnancy. They saw incremental associations between more physical activity and lower risk of developing preeclampsia or gestational hypertension. It remains to be seen whether this association is causal, and future studies designed to increase physical activity and reduce sedentary behaviour in pregnancy are needed.”

High blood pressure develops in up to 5 to 10 per cent of all pregnancies and is a leading cause of foetal and maternal disease and death.

The study had several limitations, including that 83 per cent of participants self-reported as non-Hispanic white and tended to have higher education and income levels, meaning the findings may not reflect the experiences of other population groups.