Oral antihypertensive therapy for severe hypertension in pregnancy and postpartum: a systematic review

Background Pregnant and postpartum women with severe hypertension are at increased risk of stroke and require blood pressure (BP) reduction. Parenteral antihypertensives have been most commonly studied, but oral agents would be ideal for use in busy and resource-constrained settings. Objectives To review systematically, the effectiveness of oral antihypertensive agents for treatment of severe pregnancy/postpartum hypertension. Search strategy A systematic search of MEDLINE, EMBASE and the Cochrane Library was performed. Selection criteria Randomised controlled trials in pregnancy and postpartum with at least one arm consisting of a single oral antihypertensive agent to treat systolic BP >= 160 mmHg and/or diastolic BP >= 110 mmHg. Data collection and analysis Cochrane REVMAN 5.1 was used to calculate relative risk (RR) and weighted mean difference by random effects. Main results We identified 15 randomised controlled trials (915 women) in pregnancy and one postpartum trial. Most trials in pregnancy compared oral/sublingual nifedipine capsules (8-10 mg) with another agent, usually parenteral hydralazine or labetalol. Nifedipine achieved treatment success in most women, similar to hydralazine (84% with nifedipine; relative risk [RR] 1.07, 95% confidence interval [95% CI] 0.98-1.17) or labetalol (100% with nifedipine; RR 1.02, 95% CI 0.95-1.09). Less than 2% of women treated with nifedipine experienced hypotension. There were no differences in adverse maternal or fetal outcomes. Target BP was achieved similar to 50% of the time with oral labetalol (100 mg) or methyldopa (250 mg) (47% labetelol versus 56% methyldopa; RR 0.85 95% CI 0.54-1.33). Conclusions Oral nifedipine, and possibly labetalol and methyldopa, are suitable options for treatment of severe hypertension in pregnancy/postpartum.