Comparison of oral enalapril-hydrochlorothiazide and oral nifedipine in treating postpartum hypertension: an open label randomized controlled trial

Background: Postpartum hypertension is a common complication following hypertensive disorders of pregnancy and is associated with increased short- and long-term cardiovascular risk. Evidence guiding optimal oral antihypertensive therapy in the postpartum period remains limited. Objective: To compare the efficacy and safety of oral nifedipine vs a combination of enalapril–hydrochlorothiazide in the management of postpartum hypertension. Methods: This open-label, randomized controlled trial was conducted at a tertiary care institute between February 2024 and February 2025. Women with systolic blood pressure (SBP) >140 mmHg and/or diastolic blood pressure (DBP) >90 mmHg occurring from delivery up to 6 weeks postpartum were enrolled. Participants were randomized to receive either oral nifedipine (Group A, n=80) or oral enalapril–hydrochlorothiazide (Group B, n=83). The primary outcome of the study was the sustained blood pressure control defined as absence of episodes of severe blood pressure defined as SBP>160 mmHg and DBP>110 mmHg for minimum of 48 hours. Secondary outcomes included time required to achieve target blood pressure (defined as SBP<140 mmHg and DBP<90 mmHg), mean change in SBP and DBP, number of doses required to achieve target BP, requirement of additional antihypertensive drugs, total duration of drug requirement, maternal complications due to raised BP, any side effects associated with drug intake and mean BP at 1-week and 6-week follow-up. Intention-to-treat analysis was performed. Results: Sustained BP control for 48 hours did not differ significantly (63.75% vs 72.2%; P=.242) among the groups. However, post-treatment mean SBP was significantly lower in the enalapril–hydrochlorothiazide group (SBP: 138.3±11.69 vs 133.0±11.31 mmHg, mean difference, −5.3 mmHg; P=.003). Similarly, mean DBP was significantly lower in Group B than in Group A (84.8±9.14 vs 88.0±7.66 mmHg; mean difference, −3.2 mmHg; P=.02). The percentage reduction in SBP and DBP was also greater with combination therapy. Both groups achieved BP control within a comparable time frame (3.65±1.77 vs 3.76±1.6 hours; P=.101). Additionally, the need for additional antihypertensive medication was significantly higher in the nifedipine group (28.7% vs 14.4%; P=.02). Adverse effects were mild and comparable between groups, with no maternal complications observed. Conclusion: Enalapril–hydrochlorothiazide provided greater blood pressure reduction and reduced the need for additional antihypertensive therapy compared with nifedipine in the management of postpartum hypertension.