High blood pressure during pregnancy has doubled, but only 60% are treated: Study

Rates of high blood pressure during pregnancy doubled between 2008-2021, but only 60% were treated for it, according to a new study published Monday in the journal Hypertension.

"One of the main drivers of adverse outcomes during pregnancy is due to high blood pressure," Stephanie Leonard, an Assistant Professor of Obstetrics and Gynecology- Maternal Fetal Medicine at Stanford and lead author on the study, told ABC News.

Chronic hypertension in pregnancy is defined as high blood pressure diagnosed before pregnancy or before 20 weeks of pregnancy.

While it's not clear why rates have increased so dramatically, prior research suggests it may be because more people are choosing to wait until they are older to have children.

Chronic hypertension can lead to serious complications that can be dangerous for pregnant people and their babies. The U.S. maternal death rate remains the highest among high-income countries, with Black women experiencing the highest rates and they are also disproportionately affected by hypertension in pregnancy.

"Heart disease is the number one cause of death of women in the U.S., and women have unique risk factors as compared to men," Maria Pabon, a cardiologist at Brigham and Women's Hospital specializing in women's cardiovascular health, said in an email to ABC News.

"High blood pressure during pregnancy can increase the risk of different kinds of heart disease in the future," Pabon said.

But doctors say there are concrete steps people can take to lower their risk.

"Being aware that having a history of high blood pressure during pregnancy can increase your risk of future heart disease," Pabon said. She encourages lowering other risk factors for developing heart disease by eating a heart-healthy diet, such as the Mediterranean diet, and working on exercise, sleep, and stress management.

Annual screening for heart disease should include checking "blood pressure, weight, and cholesterol. Everyone should have a Lipoprotein A level checked once," Pabon said.

If you have a family history of heart disease, Pabon recommends seeing a cardiologist specializing in women's health or prevention cardiology to consider other testing.

Ask your doctor if you should check your blood pressure at home. If you have a blood pressure monitor at home, bring it to your next appointment to check for fit and accuracy.

The American Heart Association has tips for checking your blood pressure at home.

• Don't smoke, drink caffeinated beverages or exercise within 30 minutes before taking your blood pressure.
• Don't take measurements over clothes.
• Rest for five minutes before checking and sit still.
• Check at the same time every day.
• Sit up straight with your back supported and feet flat on the floor. Rest your arm on a flat surface.
• Take multiple measurements and record the numbers.

According to the new study, not enough people are getting treatment for their high blood pressure during pregnancy, with the study estimating that only 60% are treated.

Typically, anyone with high blood pressure during pregnancy is treated with medication if blood pressure is above 140/90.

Dr. Justin Brandt, an Associate Professor in the Department of Obstetrics and Gynecology at NYU Grossman School of Medicine and the Division Director of Maternal Fetal Medicine, said 60% may be an underestimate because not all doctors are aware of updated medical consensus about treating hypertension during pregnancy.

In 2022, a major medical group updated its guidance to commend treating people even with mild hypertension during pregnancy - a shift from prior guidance , which said to start medication if blood pressures were above 160/110.

"Our approach really changed. We realized that treatment reduced complications in pregnancy like pre-eclampsia without affecting fetal growth," Brandt said.

Lindsey Ulin, MD is a resident in internal medicine at Brigham and Women's Hospital and a member of the ABC News Medical Unit.