Chronic hypertension during pregnancy doubled in the US between 2007 and 2021

NIH-funded research has shown that the disease is poorly treated, suggesting the need for improved strategies.

The prevalence of chronic high blood pressure during pregnancy in the United States doubled from 2007 to 2021, but only about 60% of patients with the potentially life-threatening condition were treated with antihypertensive medications, according to a National Institutes of Health (NIH)-supported study of nearly 2 million pregnancies. The study, funded by NIH's National Heart, Lung, and Blood Institute (NHLBI), did not explore reasons for the increase, but researchers say older mothers, rising rates of obesity, and other factors likely play a role. The findings were published today in the journal Neurology. High blood pressure.

“These findings are of serious concern because of the high maternal mortality rates associated with chronic hypertension during pregnancy in the United States,” said study leader Dr. Stephanie Leonard, an epidemiologist at the Stanford University School of Medicine in California. “Despite the existence of safe and effective treatments for chronic hypertension, this study speaks to the urgent need for improved care for this serious disease.”

Chronic hypertension during pregnancy is defined as persistent high blood pressure of 140/90 millimeters of mercury (mmHg) or higher before or within 20 weeks of pregnancy. pregnancyThe disease can damage a pregnant woman's organs and increase the risk of premature birth and low birth weight babies. If undetected and untreated, it can be fatal.

The study is especially relevant for Black, American Indian and Alaska Native people, who have the highest rates of poor maternal health and pregnancy-related mortality in the country.

“We need to better understand the gaps in the treatment of chronic hypertension, especially in these high-risk groups,” said Candace A. Price, PhD, program director for women's health research at NHLBI. “If we don't detect and treat chronic hypertension early, we miss an opportunity to protect our heart health during and after pregnancy.”

In the study, researchers used a large database of U.S. commercial insurance claims from 2007 to 2021 to analyze the prevalence of chronic hypertension among 1.9 million pregnant women aged 12 to 55 years and the use of oral antihypertensive medications during this period.

The researchers found that the proportion of pregnant women with chronic hypertension has more than doubled, from 1.8% in 2008 to 3.7% in 2021. They also found that the proportion of pregnant women with chronic hypertension using antihypertensive medications remained stable over the study period, increasing only slightly from 58% to 60%.

Although the causes of the sharp increase in chronic hypertension during pregnancy were not the focus of the study, Leonard noted that the increase is consistent with trends in hypertension observed in various time periods prior to the study, as well as trends in the U.S. adult population as a whole.
Advance analysis For example, national data from 1970 to 2010 suggest that the increasing trend in chronic hypertension during pregnancy is due in part to women giving birth at an older age. In this study, the researchers found that women with chronic hypertension tended to be older than those without it.

Rising rates of obesity may also be contributing to the increase, as may other factors such as greater vigilance in diagnosing chronic hypertension and improved medical record-keeping regarding its development.

Leonard and his colleagues analyzed the potential impact of updated hypertension guidelines from the American College of Cardiology and the American Heart Association in 2017, which lowered the threshold for diagnosing hypertension for all adults. But they found no association, at least for now.

The blood pressure criteria changed from 140-159/90-109mmHg to 130-139/80-89mmHg for a Stage 1 diagnosis, and from 160/110mmHg or higher to 140/90mmHg or higher for Stage 2, which represents the highest health risk. Leonard said the impact of the guidelines could show up in analyses beyond the 2008-2021 period she and her team studied.

to manage High Blood Pressure During PregnancyExperts recommend that women monitor and control their blood pressure at home, visit their doctor frequently, and take their blood pressure medications as prescribed.

This research was supported by grants K01HL171699 and R01HL139844 from the NHLBI and grant UL1TR003142 from the NIH's National Center for Advancing Translational Science Clinical and Translational Science.

study: Leonard, S., Siadat S., Main E., et al. Chronic Hypertension During Pregnancy: Prevalence and Treatment in the United States, 2008-2021. [2024] High blood pressureDOI: 10.1161/HYPERTENSIONAHA.124.22731