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

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.