What Agent Is Best for Managing Acute Hypertensive Emergency in Pregnancy?

Diane J. Angelini, EdD, CNM, FACNM, FAAN, NEA-BC

Hypertensive disorders affect as many as 10% of pregnancies worldwide. Largely because of safety concerns, hydralazine use has declined whereas labetalol and nifedipine have emerged as the most commonly used medications for hypertensive crisis during pregnancy. Researchers at one hospital in India conducted a randomized, double-blind trial to compare these two agents for their ability to lower blood pressure (BP) rapidly during an acute hypertensive emergency in pregnancy. Sixty pregnant women (age range, 18–45; ≥24 weeks' gestation; BP ≥160/110 mm Hg) were randomized to oral nifedipine plus intravenous placebo or intravenous labetalol plus oral placebo. After 20 minutes, if BP remained above 150/100, another dose was administered for up to five cycles. Nifedipine doses were constant (10 mg) for all cycles, while labetalol doses escalated from 20 mg to a maximum of 80 mg.

Median time to achieve the targeted BP of 150/100 was 40 minutes (2 doses) for nifedipine, versus 60 minutes (3 doses) for labetalol (P=0.008). Mean maternal heart rate increased significantly in the nifedipine group to 97±10.3 beats per minute; however, maternal and neonatal outcomes were similar in both groups, and no participants in either group experienced hypotension.