Racial Differences in Postpartum Blood Pressure Trajectories Among Women After a Hypertensive Disorder of Pregnancy

Question Does postpartum blood pressure trajectory after a hypertensive disorder of pregnancy differ by race? Findings In this prospective cohort study that included 1077 women after a hypertensive disorder of pregnancy, blood pressure trajectories evaluated using mixed-effects linear regression models differed significantly by self-reported race. At the conclusion of the study, 68% of Black women and 51% of White women met the criteria for stage 1 or stage 2 hypertension. Meaning This study suggests that postpartum blood pressure trajectories indicate persistence of higher blood pressures among Black women in this cohort, which may have important implications for postpartum morbidity and mortality associated with hypertensive and cardiovascular conditions in this population. This cohort study describes the blood pressure trajectory in the first 6 weeks post partum after a hypertensive disorder of pregnancy and evaluates whether blood pressure trajectories differ by self-reported race. Importance Maternal morbidity and mortality are increasing in the United States, most of which occur post partum, with significant racial disparities, particularly associated with hypertensive disorders of pregnancy. Blood pressure trajectory after a hypertensive disorder of pregnancy has not been previously described. Objectives To describe the blood pressure trajectory in the first 6 weeks post partum after a hypertensive disorder of pregnancy and to evaluate whether blood pressure trajectories differ by self-reported race. Design, Setting, and Participants This prospective cohort study included deliveries between January 1, 2018, and December 31, 2019. Women with a clinical diagnosis of a hypertensive disorder of pregnancy were enrolled in a postpartum remote blood pressure monitoring program at the time of delivery and were followed up for 6 weeks. Statistical analysis was performed from April 6 to 17, 2020. Main Outcomes and Measures Mixed-effects regression models were used to display blood pressure trajectories in the first 6 weeks post partum. Results A total of 1077 women were included (mean [SD] age, 30.2 [5.6] years; 804 of 1017 White [79.1%] and 213 of 1017 Black [20.9%]). Systolic and diastolic blood pressures were found to decrease rapidly in the first 3 weeks post partum, with subsequent stabilization (at 6 days post partum: mean [SD] peak systolic blood pressure, 146 [13] mm Hg; mean [SD] peak diastolic blood pressure, 95 [10] mm Hg; and at 3 weeks post partum: mean [SD] peak systolic blood pressure, 130 [12] mm Hg; mean [SD] peak diastolic blood pressure, 85 [9] mm Hg). A significant difference was seen in blood pressure trajectory by race, with both systolic and diastolic blood pressure decreasing more slowly among Black women compared with White women (mean [SD] peak systolic blood pressure at 1 week post partum: White women, 143 [14] mm Hg vs Black women, 146 [13] mm Hg; P = .01; mean [SD] peak diastolic blood pressure at 1 week post partum: White women, 92 [9] mm Hg vs Black women, 94 [9] mm Hg; P = .02; and mean [SD] peak systolic blood pressure at 3 weeks post partum: White women, 129 [11] mm Hg vs Black women, 136 [15] mm Hg; P < .001; mean [SD] peak diastolic blood pressure at 3 weeks post partum: White women, 84 [8] mm Hg vs Black women, 91 [13] mm Hg; P < .001). At the conclusion of the program, 126 of 185 Black women (68.1%) compared with 393 of 764 White women (51.4%) met the criteria for stage 1 or stage 2 hypertension (P < .001). Conclusions and Relevance This study found that, in the postpartum period, blood pressure decreased rapidly in the first 3 weeks and subsequently stabilized. The study also found that, compared with White women, Black women had a less rapid decrease in blood pressure, resulting in higher blood pressure by the end of a 6-week program. Given the number of women with persistent hypertension at the conclusion of the program, these findings also appear to support the importance of ongoing postpartum care beyond the first 6 weeks after delivery.