Factors associated with persistent hypertension one year postpartum in persons with gestational hypertension or preeclampsia

Objective To identify factors associated with persistent hypertension one-year postpartum after pregnancy complicated by gestational hypertension or preeclampsia. Study Design A retrospective case-control study of postpartum patients who had a diagnosis of gestation hypertension or preeclampsia during a recent pregnancy and attended one-year postpartum annual exam and blood pressure check between 2014 and 2019 in a single academic medical center. Cases were defined as persons with persistent hypertension one year postpartum, using the 2017 American College of Cardiology/American Heart Association (ACC/AHA) guidelines, defining stage I hypertension as systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥80 mmHg. Controls were defined as non-pregnant persons with normal blood pressure (BP) at one year postpartum. Using bivariate and multivariate analyses, demographic, clinical and labor characteristics were compared between persons who had persistent hypertension one-year postpartum and controls. Results Of the 595 persons included in this analysis, 268 (45.0%) had persistent hypertension one year postpartum. Bivariate analyses demonstrated that older maternal age, higher body mass index (BMI) at first prenatal visit, at delivery, and one year postpartum, mild-range BP (compared to normal BP) prior to discharge, and patients with elevated BP at 6-week postpartum visit, were more likely to have persistent hypertension one-year postpartum. In contrast, nulliparity was associated with lower risk of having persistent hypertension at one-year postpartum. Multivariate logistic regression demonstrated that mild range BP prior to discharge (aOR 1.78, 95%CI 1.16-2.72), elevated BPs at 6 weeks postpartum (aOR 2.01, 95% CI 1.36-3.00), and higher BMI at one-year postpartum (aOR 1.07, 95%CI 1.00-1.14), remained to be significantly associated with higher odds of persistent hypertension one-year postpartum, while nulliparity remained to be associated with lower odds of persistent hypertension one-year postpartum (aOR 0.55, 95%CI 0.36-0.84) Conclusion In this cohort, 45% of patients with gestational hypertension or preeclampsia had persistent hypertension one-year postpartum by the 2017 ACC/AHA hypertension definition. Patients that had mildly elevated BPs in the immediate postpartum period as well as at 6 weeks postpartum, and higher BMI one year postpartum, had higher risk of having at least stage I HTN one year following pregnancy complicated by gestational hypertension or preeclampsia.