Race alone does not explain disparities in risk of preeclampsia

Jan. 4, 2022

An analysis of medical records for a racially diverse group of more than 6,000 women has added to evidence that some combination of biological, social, and cultural factors — and not race alone — is likely responsible for higher rates of preeclampsia among Black women born in the United States compared with Black women who immigrated to the country, according to a news release from Johns Hopkins Medicine.

The data on preeclampsia, a serious form of high blood pressure that can lead to deadly outcomes for mother and fetus, were gathered over a 28-year period as part of the Boston Birth Cohort study originally designed to investigate the genetic and environmental factors associated with premature births.

The study was published in the Journal of the American Medical Association. The new analysis, led by researchers at Johns Hopkins Medicine, specifically examined differences in hypertension and other cardiovascular disease risk factors and prevalence of preeclampsia among Hispanic, Black and White women. Results showed that all three groups of women who gave birth and were born in the U.S. had a higher cardiovascular disease risk profile than foreign-born counterparts after accounting for differences in weight, smoking, alcohol use, stress and diabetes.

For Black women, birth status outside the U.S. and shorter duration of residence (those who lived in America for less than 10 years) were associated with 26% lower odds of preeclampsia. Birthplace status and duration of U.S. residence was not significantly associated with the odds of preeclampsia among Hispanic and White mothers who were born outside the U.S.

Overall, the researchers said, the findings suggest that place of birth, or “nativity,” related disparities in preeclampsia among Black women are “not fully explained” by nativity differences in sociodemographic or cardiovascular disease factors.

In the study, medical records and other information on a total of 6,069 women were analyzed. The average age of participants was 27.5 years, and subjects self-identified as Hispanic (2,400, with 76.8% born outside the U.S.), Black (2,699, with 40.5% born outside the U.S.) or White (997, with 22.2% born outside the U.S.). All women had single-child deliveries at the Boston Medical Center from October 1998 to February 2016. The overall prevalence of preeclampsia among all women was 9.5%. Black women had the highest age-adjusted prevalence of preeclampsia (12.4%) compared with Hispanic (8.2%) and white women (7.1%).

U.S.-born Black women, specifically, were also younger, had fewer years of formal education and were more often single compared with Black women who immigrated to the country. Sharma said that although not explored in this study, the stress of systemic racism, living in racially segregated neighborhoods and experiences of discrimination are likely contributors to the poor health of Black women and may therefore contribute to disparities in cardiovascular risk factors and preeclampsia. She added that lack of access to healthcare services and poor quality of care are also factors, particularly among women at lower socioeconomic levels.

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