Department of Research & Evaluation News

PASADENA, CA – Women who are diagnosed with hypertensive disorders while pregnant are more than twice as likely to develop high blood pressure in the first year after delivery as women who did not have any pregnancy-related hypertension, according to a Kaiser Permanente study published in the Journal of Hypertension.

Hypertensive disorders during pregnancy are common, affecting up to 10 percent of all pregnant women, and include gestational hypertension, preeclampsia (which is a combination of high blood pressure and proteinuria), and eclampsia, which includes seizures in women with preeclampsia.

Research has shown that hypertensive disorders in pregnancy are associated with long-term cardiovascular disease risk, but little is known about the effect of these conditions in the early years after delivery, said the study’s lead author, Mary Helen Black, PhD, MS, a researcher with Kaiser Permanente’s Department of Research & Evaluation in Southern California. Our study suggests there is a subset of women who develop hypertension in pregnancy and present with elevated blood pressure in the first year after delivery despite being otherwise healthy prior to pregnancy.

The study highlights the importance of monitoring and controlling blood pressure not only during pregnancy, but after delivery as well.

Researchers examined the electronic health records of 5,960 women who had prenatal care and delivered a baby at the Kaiser Permanente Southern California Bellflower Medical Center between 2005 and 2010. Women with pre-pregnancy high blood pressure were excluded from the analysis.

The study found that women who had a hypertensive disorder during pregnancy were 2.4 times more likely – and women with pre-eclampsia/eclampsia 2.5 times more likely – to develop pre-hypertension or hypertension in the year after delivery than those women who maintained a normal blood pressure during their pregnancy, after controlling for differences between the groups.

In comparison to women with normal blood pressure during pregnancy, women with pregnancy-related hypertension tended to be slightly younger and overweight or obese before pregnancy. In addition, they were more likely to have had one or more children previously and to gain excess weight and develop gestational diabetes during their pregnancy.

Women who develop hypertension, preeclampsia, or eclampsia in pregnancy should discuss monitoring their blood pressure after delivery with their physicians, added Black. Further research is needed to determine whether early postpartum blood pressure screening and improved follow-up and treatment of women with pregnancy-related hypertensive disorders may prevent future cardiovascular disease.

This study was supported by Kaiser Permanente Southern California Direct Community Benefit funds. 

Other authors of the study include Hui Zhou; David A. Sacks, MD; Jean M. Lawrence, ScD, MPH, MSSA; Teresa N. Harrison, SM; and Kristi Reynolds, PhD, MPH, from the Department of Research & Evaluation, Kaiser Permanente Southern California in Pasadena, and Sascha Dublin, MD, PhD, from Group Health Research Institute in Seattle.

About the Kaiser Permanente Southern California Department of Research & Evaluation

The Department of Research & Evaluation conducts high-quality, innovative research into disease etiology, prevention, treatment and care delivery. Investigators conduct epidemiology, health sciences and behavioral research as well as clinical trials. Areas of interest include diabetes and obesity, cancer, HIV/AIDS, cardiovascular disease, aging and cognition, pregnancy outcomes, women’s and children’s health, quality and safety, and pharmacoepidemiology. Located in Pasadena, California, the department focuses on translating research to practice quickly to benefit the health and lives of Kaiser Permanente Southern California members and the general population. Visit kp.org/research.

About Kaiser Permanente

Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, Kaiser Permanente has a mission to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 10 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: kp.org/share.