Optimal treatment for women with acute hypertension in pregnancy; a randomized trial comparing intravenous labetalol versus nicardipine

Objectives: Blood pressure control in severe hypertension of pregnancy is crucial for mother and neonate. In absence of evidence, guidelines recommend either intravenous labetalol or nicardipine. We compared the effectiveness and safety of these two drugs in women with severe hypertension in pregnancy. Study design: We performed an open label randomized controlled trial. Women with a singleton pregnancy complicated by severe hypertension (systolic ≥ 160 mmHg and/or diastolic ≥ 110 mmHg) requiring intravenous antihypertensive treatment were randomized to intravenous labetalol or intravenous nicardipine. The primary outcome was a composite adverse neonatal outcome defined as severe Respiratory Distress Syndrome (RDS), Broncho Pulmonary Dysplasia (BPD), Intraventricular Hemorrhage (IVH) IIB or worse, Necrotizing Enterocolitis (NEC), or perinatal death defined as fetal death or neonatal death before discharge from the neonatal intensive care unit (NICU). Based on a power analysis, we estimated that 472 women (236 per group) needed to be included to detect a difference of 15% in the primary outcome with 90% power. The study was halted prematurely at 30 inclusions because of slow recruitment and trial fatigue. Results: Between August 2018 and April 2022, we randomized 30 women of which 16 were allocated to intravenous nicardipine and 14 to intravenous labetalol. The composite adverse neonatal outcome was not significantly different between the two groups (25 % versus 43 % OR 0.28 (95 % CI 0.05–1.43), p = 0.12)). Respiratory distress syndrome occurred more often in the labetalol group than in the nicardipine group (42.9 % versus 12.5 %). Neonatal hypoglycemia occurred more often in the nicardipine group than in the labetalol group (31 % versus 7 %). Time until blood pressure control was faster in women treated with nicardipine than in women treated with labetalol (45 (15–150 min vs. 120 (60–127,5) min). Conclusion: In our prematurely halted small RCT, we were unable to provide evidence for the optimal choice of treatment for severe hypertension to improve neonatal outcome and/or to obtain faster blood pressure control. Differences in Respiratory distress syndrome and neonatal hypoglycemia between the groups might be the result of coincidental finding due to the small groups included in the study. A larger randomized trial would be needed to determine the safest and most efficacious (intravenous) therapy for severe hypertension in pregnancy. This study emphasizes the challenges of conducting a RCT for the optimal treatment for these women.