The risk of high blood pressure in pregnancy is rising—and the damage can be life-changing

It happened so fast.

It was 2019, and Megan O’Grady was 32 weeks pregnant with her first child. She took her dogs for a walk, just as she usually did. But that day, she was surprised by how tired she was. Then her chest started to hurt. Later, sitting in a restaurant with her husband, she felt miserable. She realized something was wrong. By the time she got to the hospital that night, her blood pressure was 220/120 millimeters of mercury (mm Hg)—dangerously high.

O’Grady was shocked: at a doctor visit just a few days before, her blood pressure was completely normal. But now she was suffering from severe preeclampsia—a potentially deadly pregnancy complication marked by high blood pressure and organ damage. She rapidly found herself with no choice but to give birth, more than a month before she was due.

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“It was so scary,” she recalls. “He was born, and then they were having to check my blood pressure every hour after he was born. It was crazy.”

O’Grady is far from alone. The rate of high blood pressure in pregnancy has increased by 73 percent between 2016 and 2024, according to the U.S. Centers for Disease Control and Prevention. This is a rate of about one in 10. What’s more, cases of gestational hypertension—high blood pressure that happens to someone for the first time while they are pregnant—have been rising since 1989, the first year the condition was recorded on birth certificates.

The increase can’t be easily explained by any single cause, says Sarah Kilpatrick, a maternal fetal medicine specialist at Cedars-Sinai in Los Angeles. The average age of people’s first pregnancy is going up, and more people older than age 40 are having babies. More women are having twins and triplets more often because of in vitro fertilization. And women’s body mass indexes (BMIs) have been consistently going up.

Any one of these factors is a risk for high blood pressure, Kilpatrick says, and some people might have more than one. As pregnancies progress, gestational hypertension increases the risk of preeclampsia, which also leads to liver and kidney problems. The condition is diagnosed by blood pressure readings and signs of organ damage in urine or blood tests. It can be fatal: blood pressure problems during pregnancy are one of the leading causes of illness and death in U.S. mothers. And as with O’Grady, the high blood pressure aspect of preeclampsia can come out of the blue.

“If we don’t diagnose it soon enough or people stay pregnant too long, they can get really sick and, in the extreme, of course, die,” Kilpatrick says. “That’s the problem with the disease—it can be very insidious.”

The recent CDC report found that gestational hypertension in 2024 was highest among Native American and Black women. People age 40 and older and those whose BMI was considered “obese” were also most likely to have the condition. But in general, the rates of high blood pressure in pregnancy are rising, no matter what. Baha Sibai, a maternal fetal medicine specialist at in the University of Texas Health Science Center at Houston, believes the rate could be even higher because many birth certificates have incomplete data.

A piece of data that could help doctors better understand and manage hypertension in pregnancy involves tracking how many weeks the pregnancy reached before birth, Sibai says. Once diagnosed, he says, gestational hypertension is supposed to be monitored very carefully in the interest of the woman, not just the fetus.

“All of our focus before was managing the pregnancy,” he says. “Now there is a big emphasis on how we are going to reduce morbidity in the woman.”

Preeclampsia is, at its heart, a systemic response to the placenta. An abnormal increase in a protein called sFlt-1 (soluble fms-like tyrosine kinase 1), which slows down placental growth, Kilpatrick says. This seems to be the trigger that leads to preeclampsia later.

In 2023 the U.S. approved the first blood test to diagnose preeclampsia, measuring the ratio of sFlt-1 to another placental protein that doesn’t change. Kilpatrick was involved getting it approved.

“We’ve known it’s been increasing partially because of better recognition and diagnosis,” Kilpatrick says. Still, some women may not appreciate the risks of hypertension and preeclampsia. “It should be something women know about,” she says.

When O’Grady went to the hospital, she was diagnosed with a severe form of preeclampsia, a rare condition called HELLP syndrome (the acronym is based on symptoms: hemolysis, elevated liver enzymes and low platelet levels). The staff immediately gave her magnesium sulfate to prevent her from having seizures.

“I had no concept of what that was,” she says of HELLP syndrome, “no concept that my chest pain was my liver being pushed up” because of swelling and pressure.

High blood pressure in pregnancy carries lifelong consequences, raising the risk of cardiovascular disease and recurring hypertension. This is particularly true for preeclampsia.

O’Grady recovered from her first pregnancy, and she and her husband planned carefully for their second. She went on beta-blockers in case her blood pressure started creeping up again—it did.

At 24 weeks, her blood pressure started to climb, and eventually, she was admitted to a hospital for the remainder of her pregnancy. At 28 weeks, she delivered her baby. The nurses offered to play music in the delivery room. O’Grady chose the Beatles classic “Let It Be.”

“It’s out of your control,” she says, describing that moment years later, with her two sons running around the house. Now she follows a healthy lifestyle that she hopes will ward off the risk of heart disease. “You just have to listen to your doctors and trust in their advice. You kind of have to hope that everything will be okay.”