Stage 1 hypertension before 20 weeks' gestation and associated postpartum adverse outcomes

Stage 1 hypertension, defined by the American Heart Association as a systolic blood pressure of 130 to 139 mm Hg and/or a diastolic blood pressure of 80 to 89 mm Hg, is associated with an increased risk of developing hypertensive disorders of pregnancy. However, the postpartum implications of this diagnosis remain unknown.

This study aimed to evaluate whether stage 1 hypertension before 20 weeks of gestation is associated with persistent antihypertensive medication use at 6 weeks after delivery.

This was a secondary analysis of a retrospective cohort study of all patients who delivered singleton pregnancies after 20 weeks of gestation at a tertiary care center between January 1, 2014, and June 8, 2016. Patients with a diagnosis of chronic hypertension, defined as a maximum blood pressure of ≥140/90 mm Hg before 20 weeks of gestation, and those without 6-week postpartum data were excluded. The primary outcome was antihypertensive medication use at 6 weeks after delivery, which was compared between patients with stage 1 hypertension before 20 weeks of gestation and those with normal blood pressure before 20 weeks of gestation. The secondary outcomes included the development of a hypertensive disorder of pregnancy, antihypertensive medication use at delivery discharge, postpartum readmission for hypertensive disorders of pregnancy, and blood pressure values at 6 weeks after delivery. Multivariate logistic regression was used to adjust for potential cofounders. A sensitivity analysis compared the primary outcome between the groups only among those with hypertensive disorders of pregnancy.

Of note, 465 patients (23.1%) met the criteria for stage 1 hypertension before 20 weeks of gestation. The remaining 1546 patients in the cohort were normotensive before 20 weeks of gestation, with a maximum blood pressure of <130/80 mm Hg. Compared with the group with normal blood pressure, the group with stage 1 hypertension had a higher mean age (28.2±5.7 vs 29.1±5.6 years, respectively; P=.002) and higher rates of obesity (25.0% vs 52.0%, respectively; P<.001) and pregestational diabetes mellitus (2.4% vs 5.2%, respectively; P=.002). In addition, patients with stage 1 hypertension were more likely to have a hypertensive disorder of pregnancy in the current pregnancy than those with normal blood pressure (43.0% vs 23.8%, respectively; P<.001). Patients with stage 1 hypertension were significantly more likely to require antihypertensive medication use at 6 weeks after delivery than those with normal blood pressure (8.8% vs 2.9%, respectively; aOR, 2.23 [95% CI, 1.41-3.54]), even when the analysis was restricted to those diagnosed with a hypertensive disorder of pregnancy (P=.02). In addition, patients with stage 1 hypertension were more likely to be readmitted after delivery for a hypertensive disorder of pregnancy than those with normal blood pressure (3.9% vs 1.5%; aOR, 2.11 [95% CI, 1.10-4.06]).

Stage 1 hypertension before 20 weeks of gestation is a risk factor for hypertensive disorders of pregnancy, persistent antihypertensive medication use at 6 weeks after delivery, and postpartum readmission for hypertension, suggesting that close postpartum surveillance is needed in this patient population. El resumen está disponible en Español al final del artículo.