Postpartum blood pressure trends are impacted by race and BMI

Our objective was to evaluate postpartum blood pressure trends, and time to resolution of hypertension among women with hypertensive disorders of pregnancy, specifically focusing on impact of race and BMI on these trends.

We performed a secondary analysis of a randomized trial that utilized a text-message based home blood pressure monitoring system. BPs for this study included both inpatient postpartum BPs as well as home BPs obtained from the text-based program. Women were followed from 12 h of delivery to 16 days postpartum. Outcomes were: (1) postpartum BP trend summaries from a linear mixed-effects regression model and (2) time to resolution of hypertension (defined as ≥ 48 h of BPs < 140/90) depicted using Kaplan Meier survival curves with hazard ratio estimates of association using Cox models.

Eighty-four women were included, of which 63% were black. Non-black women with a BMI < 35 kg/m² had steady decreases in systolic BP whereas other groups peaked around 6.5 days postpartum. BPs for women in the BMI < 35 group, regardless of race, remained in the normotensive range. Conversely, women with a BMI ≥ 35 had a systolic BP peak into the hypertensive range prior to declining. Diastolic BP peaked at an average of 8.5 days postpartum. Time to resolution of BPs differed by race and BMI groups (p = 0.012). Non-black women with a BMI < 35 had the shortest time to resolution and 81% of these women had resolution of hypertension. Only 49% of black women with a BMI < 35 had resolution of hypertension and approximately 40% of both black and non-black women with BMI ≥ 35 had resolution of hypertension.

We identified race and BMI to be determinants of postpartum BP trends and hypertension resolution. Further study is needed to determine if race and BMI targeted postpartum hypertension interventions may lead to faster blood pressure recovery and lower maternal morbidity postpartum.