Black women face greater stroke risk after hypertensive disorders of pregnancy
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Key takeaways:
- Among Black women, those who had hypertensive disorders of pregnancy had elevated risk for stroke.
- Gestational hypertension conferred greater stroke risk than preeclampsia in Black women.
The long-term stroke risk for Black women rose by an estimated 66% if they had history with hypertensive disorders of pregnancy, possibly contributing to their overall higher incidence of stroke compared with other racial groups, data show.
Because hypertensive disorders of pregnancy such as preeclampsia and gestational hypertension are more common in Black women, the findings could help explain why stroke rates are higher in Black women than in white women, the researchers wrote in NEJM Evidence.
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“Black women are disproportionately affected by both stroke and pregnancy complications,” Shanshan Sheehy, MD, ScD, assistant professor of medicine at Boston University, told Healio. “Our study provides evidence that pregnancy history may be an important factor for risk assessment and prevention of long-term stroke. Cardiovascular screening recommendations for Black women in particular should take history of hypertensive disorders of pregnancy into account.”
The study included 42,924 women from the Black Women’s Health Study who had given birth at least once and had no CVD history. At the time of enrollment, participants ranged from age 21 to 69 years, with a median age 38 years.
“Black women have a disproportionately higher burden of both preeclamptic pregnancy and stroke compared with white women, but virtually all existing evidence on this possible association has been generated from women of European ancestry,” Sheehy told Healio. “To address the knowledge gap in Black women, we examined the relation of hypertensive disorders of pregnancy, and preeclampsia in particular, to long-term stroke risk in a large prospective cohort of self-identified Black women.”
Hypertensive disorders of pregnancy was defined as self-reported gestational hypertension and/or preeclampsia on the study’s biennial questionnaires. Strokes were also self-reported on the questionnaires and verified against medical records.
Among 4,938 women with hypertensive disorders of pregnancy history, 310 had strokes (incidence rate, 2.83 per 1,000 person-years), whereas among 37,986 women without hypertensive disorders of pregnancy history, 1,245 had strokes (incidence rate, 1.8 per 1,000 person years), the researchers wrote.
During a median 22 years of follow-up, Black women were more likely to have a stroke if they had history of any hypertensive disorders of pregnancy (HR = 1.66; 95% CI, 1.46-1.89) when adjusted for age at first birth, BMI at age 18 years, educational attainment and parental history of stroke.
Women had a greater stroke risk if they had history of gestational hypertension (HR = 1.81; 95% CI, 1.53-2.13) vs. history of preeclampsia (HR = 1.53; 95% CI, 1.29-1.82), a difference consistent with prior studies of white women, the researchers wrote.
“We speculate that hypertensive disorders of pregnancy subtypes may be more complicated than representing simply a spectrum of severity and may represent different disease phenotypes,” Sheehy told Healio.
Researchers estimated that 7% (95% CI, 5-9) of the cohort’s stroke cases were attributable to hypertensive disorders of pregnancy, with population-attributable fractions of 6% (95% CI, 3-9) for preeclampsia and 9% (95% CI, 6-12) for gestational hypertension.
In a secondary analysis of the 576 strokes that could be confirmed, the researchers found that Black women with any hypertensive disorders of pregnancy history had a multivariable HR for stroke of 1.73 (95% CI, 1.41-2.13). For women who experienced preeclampsia and gestational hypertension, the HRs were 1.63 (95% CI, 1.23-2.16) and 1.85 (95% CI, 1.41-2.43), respectively.
Sheehy told Healio that future research should be done on Black women outside of the U.S., as the study’s focus was on Black women in the U.S.
For more information:
Shanshan Sheehy, MD, ScD, can be reached at shl607@bu.edu.
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