Abstract
OBJECTIVE: To evaluate associations among antepartum pulse pressure and maternal and perinatal outcomes in women with mild chronic hypertension. METHODS: Secondary analysis of the CHAP (Chronic Hypertension and Pregnancy) trial, an open-label randomized controlled trial of antihypertensives (vs none) for mild chronic hypertension (blood pressure below 160/105 mm Hg). Patients without pulse pressure information or outcomes were excluded. The exposure was mean pulse pressure using clinic measurements after enrollment but before delivery, and the primary analysis assessed whether mean pulse pressure was associated with an adverse composite outcome. This composite included preeclampsia with severe features, medically indicated preterm birth (PTB) before 35 weeks of gestation, placental abruption or fetal or neonatal death, and small-for-gestational-age (SGA) birth weight. Logistic regression models were adjusted for randomization assignment. RESULTS: Two thousand three hundred twenty-five patients were eligible. The mean (SD) pulse pressure among patients was 50.2 (7.9) mm Hg. Increasing mean antepartum pulse pressure was associated with an increasing frequency of the adverse composite outcome (adjusted odds ratio [aOR] per 5 mm Hg 1.1; 95% CI, 1.0-1.2), preeclampsia with severe features (aOR 1.2; 95% CI, 1.0-1.1), and indicated PTB before 35 weeks of gestation (aOR 1.1; 95% CI, 1.0-1.2). Conversely, increasing pulse pressure was associated with decreasing rates of SGA birth weight below the 5th percentile (aOR 0.9; 95% CI, 0.9-1.0) but was not associated with SGA birth weight below the 10th percentile (aOR 0.9; 95% CI, 0.9-1.0). CONCLUSION: Increasing pulse pressure was modestly associated with an adverse composite, specifically preeclampsia with severe features and indicated PTB before 35 weeks of gestation, but it was negatively associated with SGA birth weight less than the 5th percentile. The role of antepartum pulse pressure in reducing adverse pregnancy outcomes in patients with chronic hypertension should be further investigated.