Maternal hypertension and associated pregnancy complications among African-American and other women in the United States

Abstract

Objective: To characterize maternal hypertension and related pregnancy complications among African-American and other women in the United States.

Methods: Using data from the National Hospital Discharge Survey, we analyzed the incidence and clinical spectrum of maternal hypertension among African-American women who delivered in hospital during 1988-1992. Maternal hypertension consisted of pregnancy-induced hypertension and chronic hypertension preceding pregnancy, including pregnancy-aggravated hypertension. Pregnancy-induced hypertension included preeclampsia, eclampsia, and transient hypertension. Incidence rates (per 1000 deliveries) and 95% confidence intervals (CI) were calculated by type of hypertension and demographic characteristics. Risk ratios and 95% CIs for adverse pregnancy outcomes among women with hypertension were also calculated.

Results: The overall incidence of all causes of maternal hypertension was 64.2, and of chronic hypertension preceding pregnancy it was 25.0 per 1000 deliveries among African-American women, an excess of 15.6 and 14.5 cases per 1000 deliveries, respectively, compared with rates for other women. The risks of preterm delivery and inadequate fetal growth were similarly increased for all hypertensive women, regardless of race. However, hypertensive African-American women were at a threefold greater risk of pregnancies complicated by antepartum hemorrhage, an association that was not observed, in other women. Development of preeclampsia and eclampsia irrespective of race was about four times higher among women with chronic hypertension preceding pregnancy than among those without chronic hypertension.

Conclusion: The excess incidence of maternal hypertension, particularly chronic hypertension, may contribute to adverse maternal and fetal pregnancy outcomes and the disparity in outcomes observed between African-American and other women in the U.S. These findings provide a specific focus for further clinical outcomes research and assessment of prenatal management in African-American women.