Postpartum hypertension is a common medical complication of pregnancy and is associated with increased healthcare utilization, including unplanned interactions with the medical system and readmission, which can add significant stress to both a newly postpartum patient and the medical care delivery system. We currently do not know the best antihypertensive treatment for postpartum hypertension and tend to use antihypertensives commonly used during pregnancy. However, the mechanism of action of ACE inhibitors may be well suited for the pathophysiology of hypertension in the postpartum period and may help provide better control of hypertension and, in turn, decrease healthcare utilization.
To determine if enalapril is superior to nifedipine at preventing prolonged hospitalizations, unplanned medical visits and/or readmission in women with postpartum hypertension.
We performed an open label, randomized controlled trial (clinicaltrials.gov registered: NCT04236258) recruiting patients ≥18 years old with chronic hypertension, gestational hypertension, or preeclampsia to receive either enalapril 10mg daily or nifedipine ER 30mg daily as an initial antihypertensive agent in the period from delivery to 6 weeks postpartum. Recruitment occurred at a tertiary academic hospital from 01/2020 to 02/2021. Exclusion criteria included being on an antihypertensive when pregnancy started or requiring ≥2 daily antihypertensives during pregnancy. The antihypertensive regimen was managed by the participants’ obstetrical provider after the initial randomization. Primary outcome was a composite of prolonged hospitalization, unplanned clinic visits, triage visits, and/or readmission. Forty patients in each arm were needed to detect a decrease in the primary outcome rate from 70% to 40% (α 0.05, power 0.80). Analyses were performed as intention-to-treat and each arm was oversampled given the risk of dropouts.
Forty-seven patients were randomized to each arm. Aside from mode of delivery and twin gestation, maternal demographics were similar in the two groups. The primary outcome occurred in 31/47 patients (66%) randomized to nifedipine and 30/47 (64%) randomized to enalapril (p = 0.83). There was no significant difference in the primary outcome after controlling for mode of delivery and twin gestation. More patients in the enalapril arm had a second antihypertensive added during their primary hospitalization (16 vs. 6) and more patients in the nifedipine arm were still on their antihypertensive at 2 weeks postpartum (42 vs. 36). There were no adverse events in either group.
Enalapril was not superior to nifedipine when used as an initial antihypertensive in the immediate postpartum period at decreasing healthcare utilization.

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