Kaiser Permanente study shows patterns reveal differences in risk in women with and without hypertensive disorders of pregnancy
Routine blood pressure measurements taken during the first 20 weeks of pregnancy can be separated into 6 distinct patterns that reveal an increasing gradient of risk for developing hypertension up to 14 years after giving birth, a new Kaiser Permanente prospective study found.
Moreover, the early pregnancy blood pressure patterns identified increasing levels of risk of post-pregnancy hypertension regardless of whether a woman developed a hypertensive disorder of pregnancy, such as preeclampsia or gestational hypertension.
“Our study found that a woman’s blood pressure pattern during the first half of pregnancy tells a story about how well her blood vessels are adapting to the demands of pregnancy that can also reveal her risk of developing hypertension later in life,” said senior author Erica P. Gunderson, PhD, MPH, a senior research scientist at the Kaiser Permanente Northern California Division of Research and a professor at the Kaiser Permanente School of Medicine. “These 6 blood pressure patterns not only distinguished levels of risk of hypertension after pregnancy among patients who developed hypertensive disorders during pregnancy but identified patients at higher risk even among those unaffected by these disorders of pregnancy.”
The study published in Hypertension included close to 175,000 women without high blood pressure, no prior diagnosis of heart, kidney or liver disease, or history of preeclampsia. The women began receiving prenatal care before their 14th week of pregnancy and gave birth at a Kaiser Permanente Northern California (KPNC) hospital between 2009 and 2019. Within the study cohort, 63,297 patients were white, 44,216 were Asian, 46,289 were Hispanic, and 12,708 were Black.
Blood pressure patterns
On average, each woman had her blood pressure measured and recorded at 4 different prenatal care visits during the first half of her pregnancy.
Electronic health records were used to obtain blood pressure measurements, to determine the presence or absence of a hypertensive disorder of pregnancy, and to identify the women who were newly diagnosed with hypertension up to 14 years after their pregnancy.
About 4.8% of women included in the study were diagnosed with hypertension from 2 months to 14 years after giving birth.
The women who had moderate- and high-risk blood pressure patterns during early pregnancy and developed preeclampsia or gestational hypertension had up to a 27 times higher risk of being diagnosed with hypertension after pregnancy compared to the group with the lowest risk blood pressure patterns who did not develop a hypertensive disorder of pregnancy.
Among patients who did not develop a hypertensive disorder of pregnancy, those with the highest risk blood pressure patterns had up to 11 times higher risk of a hypertension diagnosis after pregnancy compared to those with the lowest risk blood pressure patterns.
“These women are not currently recognized as at high risk for later life hypertension and cardiovascular disease because they did not develop a hypertensive disorder of pregnancy — but their blood pressure trajectory during early pregnancy informs us that they are,” said first author James Roberts, MD, a professor at the Magee-Womens Research Institute at the University of Pittsburgh.
Previous studies estimating risk of hypertension and cardiovascular disease in patients with a history of hypertensive disorders of pregnancy have not involved blood pressure measurements for risk stratification to predict future hypertension or cardiovascular disease later in life.
“Our study enhances precision medicine by using routine pregnancy blood pressure measurements in patients with or without a history of hypertensive disorders of pregnancy to improve risk assessments,” said Gunderson. “These routine measurements are standard for prenatal care and their wide accessibility, even in low-resourced settings, make this an important tool for clinical care and early intervention of cardiovascular disease in women.”
Pregnancy and cardiovascular disease
Cardiovascular disease is the leading cause of death in women. High blood pressure (hypertension) is often the first type of cardiovascular disease to develop, and studies show that treatments that reduce high blood pressure can decrease future risk of heart attacks and strokes.
Previous research has shown that women who develop hypertensive disorders of pregnancy, such as preeclampsia, have a 2.5- to 4-fold increased risk of hypertension and are at increased risk of developing cardiovascular disease later in life. Since 2011, the American Heart Association has included hypertensive disorder of pregnancy as a risk factor for cardiovascular disease.
“It is amazing that 4 blood pressures in the first half of pregnancy can predict blood pressure years later,” said Roberts. “It seems that how the heart and blood adapt to pregnancy predicts how they will respond to stress of aging.”
A previous study led by Gunderson developed and validated the 6 early pregnancy blood pressure patterns that increased the ability to predict early- and late-onset preeclampsia and gestational hypertension in the second half of pregnancy above clinical and social risk factors. The predictive model performed well in the Asian, Black, Hispanic, and white women in the study cohort.
“We have increasingly come to realize that pregnancy provides a window into future health and disease,” said study co-author Mara Greenberg, MD, a DOR adjunct investigator and a maternal-fetal medicine specialist with The Permanente Medical Group. “Researchers and clinicians are still working to understand how this window can be best used to optimize care for this important population. Identifying pregnancy blood pressure trends that are a risk factor for later-life cardiometabolic disease, is a promising step toward future efforts to provide precision preventive medicine.”
This study was funded by the National Heart, Lung, and Blood Institute.
Co-authors include Stacey Alexeeff, PhD, Baiyang Sun, PhD, Alexis King, PhD, Mai Nguyen-Huynh, MD, MAS, and Alan Go, MD, of the Division of Research.
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About the Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes, and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and society at large. KPDOR seeks to understand the determinants of illness and well-being and to improve the quality and cost-effectiveness of health care. Currently, DOR’s 720-plus staff, including 73 research and staff scientists, are working on nearly 630 epidemiological and health services research projects. For more information, visit divisionofresearch.kp.org or follow us @KPDOR.
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