Pregnancy-related high blood pressure rose 73 percent since 2016, CDC data show

The share of American mothers diagnosed with high blood pressure during pregnancy rose 73 percent over an eight-year span, according to federal data released this summer, a trend that has pushed the condition to affect roughly one in every ten births nationwide by 2024.

The finding comes from a National Vital Statistics Report issued by the Centers for Disease Control and Prevention's National Center for Health Statistics, which analyzed birth certificate data covering nearly every baby born in the United States from 2016 through 2024. Coverage of the report has continued to spread through regional newsrooms this week, more than three weeks after its initial publication, as obstetricians field questions from patients about what the numbers mean for their own pregnancies.

What the data show

Gestational hypertension — high blood pressure that develops during pregnancy and includes both pregnancy-induced hypertension and preeclampsia — was recorded in 6.0 percent of U.S. births in 2016. By 2024 that rate had climbed to 10.4 percent, the CDC report found, a statistically significant increase that held steady at roughly 7 percent a year throughout the period.

In raw numbers, the count of affected births grew from about 235,700 in 2016 to more than 377,200 in 2024, even as the total number of U.S. births declined slightly over the same years. The rate increased in every state and the District of Columbia without exception, though the size of the jump varied widely, from a 21 percent rise in Idaho to a 144 percent surge in Hawaii.

By 2024, nine states and the District of Columbia had rates below 9.0 percent, led by New Jersey at 6.9 percent, while eight states had rates of 13.0 percent or higher, topped by Louisiana at 14.6 percent and Alaska at 14.5 percent. The report also found the rate nearly doubled — from roughly 12.4 percent to 17.0 percent — among mothers carrying twins or higher-order multiples, compared with a rise from 5.8 percent to 10.2 percent for mothers with a single baby.

Who is most affected

The increase touched every demographic group the CDC tracked, but not equally. Rates in 2024 ranged from a low of 7.1 percent among Asian mothers to a high of 13.2 percent among American Indian and Alaska Native mothers, who along with Black mothers — at 12.3 percent — recorded the steepest rates overall. By age, mothers 40 and older had the highest rate, at 12.2 percent, while the rate rose fastest in relative terms among Asian mothers, more than doubling from 3.5 percent to 7.1 percent.

Body weight before pregnancy also tracked closely with risk: mothers classified as obese had a 15.4 percent rate in 2024, compared with 5.5 percent among underweight mothers. Mothers younger than 20 had the lowest overall rate among age groups in 2024, at 10.2 percent, edging out the 30-to-34 group.

Dr. Marc Wilson, an OB-GYN at Texas Health Denton, said the pattern lines up with a set of known and suspected risk factors he watches for in his own practice, including advanced maternal age, first pregnancies, obesity, diabetes, kidney disease, autoimmune conditions and pregnancies conceived through assisted reproductive technology. But the CDC researchers stopped short of identifying a single driver, and the report's authors noted the agency's data cannot explain why the trend has been so broad-based, cutting across income levels, regions and risk profiles alike.

"It has to be something environmental, something external," said Dr. Marc Wilson, an OB-GYN at Texas Health Denton, in comments to public radio station KERA, pointing to possible contributors ranging from microplastics and processed foods to the rising average age at which women give birth.

Why it matters

Hypertensive disorders of pregnancy, which also include chronic hypertension and eclampsia, are among the leading causes of severe maternal illness and death in the United States, according to the CDC's pregnancy mortality surveillance data. Left unmanaged, gestational hypertension can progress to preeclampsia, which the American College of Obstetricians and Gynecologists describes as a condition that can cause organ damage in the mother and, in the most severe cases, seizures, stroke or death. The disorders are also linked to higher risks of stillbirth, preterm birth and low birthweight for infants.

The CDC's own patient guidance on high blood pressure during pregnancy lists warning signs that can signal the condition is worsening, including:

• Persistent headaches that do not improve with rest or medication
• Changes in vision, such as blurriness or seeing spots
• Swelling in the face or hands
• Pain in the upper right side of the abdomen
• Rapid, unexplained weight gain
• Shortness of breath

Physicians note that many cases produce no symptoms at all, which is why routine blood pressure checks at every prenatal visit remain the primary way the condition is caught early. Dr. Wilson said standard management includes closer monitoring, low-dose aspirin started before 20 weeks for women with known risk factors, reduced sodium intake, and in some cases blood pressure medication or modified bed rest.

An imperfect but telling data set

The CDC report's authors caution that birth certificate data likely undercounts the true prevalence of gestational hypertension, citing prior validation studies that found sensitivity as low as 20 to 50 percent in some reporting areas — meaning the real rate of the condition could be even higher than the birth certificate figures suggest. The agency also flagged instances of large hospitals reporting suspiciously few or zero cases compared with similarly sized facilities, a sign of possible underreporting rather than genuinely low rates.

Even with those limitations, researchers say the consistency of the increase — across every state, every age group, every racial and ethnic category, and both single and multiple births — makes the overall trend hard to dismiss as a reporting artifact alone. The report builds on earlier CDC findings that gestational hypertension rates had already risen 108 percent between 1989 and 2016, suggesting the condition has been on a sustained upward trajectory for more than three decades.

What happens next

The U.S. Preventive Services Task Force has since 2023 recommended low-dose aspirin for pregnant women at high risk of preeclampsia, a preventive step obstetricians say is likely to see wider use as awareness of the data grows. Maternal health researchers are expected to continue probing potential causes, including the role of rising obesity rates, delayed childbearing, greater use of fertility treatments and possible environmental exposures, though no single explanation has been confirmed.

For now, the CDC and outside physicians are emphasizing consistent prenatal care as the most reliable defense, since the condition is treatable when caught early but can escalate quickly when it is not. The agency's National Center for Health Statistics has not indicated when it will next update the figures, though gestational hypertension has been tracked on birth certificates since 1989 and is reviewed periodically as new natality data become available.