Nifedipine Could Help Reduce Severe Hypertension in Women with Preeclampsia

Erin M. Cleary, MD

A randomized trial suggests use of intrapartum extended-release nifedipine could help prevent severe hypertension among pregnant individuals with preeclampsia.

Results of the trial, which randomized 110 individuals, suggest use of nifedipine was associated with reducing in intrapartum acute hypertensive therapy among individuals with preeclampsia with severe features, with further analysis pointing to a lower rate of cesarean delivery compared with placebo therapy.

“We know that bringing down very high blood pressure to a safer range will help prevent maternal and fetal complications. However, besides rapid-acting, IV medicines for severe hypertension during pregnancy, optimal management for hypertension during the labor and delivery process, has not been studied,” said lead investigator Erin M. Cleary, MD, assistant professor of clinical obstetrics and gynecology at the Indiana University School of Medicine, in a statement.

A dihydropyridine calcium channel blocker, nifedipine received initial approval in 1981. Since, multiple formulations, including an extended-release version, have received approval and been examined for a slew of hypertensive disorders. Cleary, who was a fellow in maternal fetal medicine at The Ohio State University (OSU), when the study was conducted, and a team of colleagues from OSU designed the current study to assess whether use of extended-release nifedipine might help prevent severe blood pressure levels from developing and use of IV medications.

With this in mind, investigators conducted the randomized, triple-blind, placebo-controlled trial from June 2020-April 2022 at the OSU Wexner Medical Center. During that time, 365 individuals underwent screening and 110 underwent subsequent randomization, with 55 randomized to nifedipine and 55 randomized to placebo. For inclusion in the trial, individuals needed to be at least 22 weeks pregnant, diagnosed with severe preeclampsia, and undergo induction of labor. Those randomized to nifedipine were instructed to take a single 30 mg pill of nifedipine extended-release each day until delivery.

The primary outcome of interest for the trial was the receipt of 1 or more doses of acute hypertension therapy for severe blood pressure, which was defined as 160/110 mmHg or greater, sustained for a period of 10 minutes or longer. Secondary outcomes of interest included route of delivery, neonatal, intensive care unit (ICU) admission, and a composite of adverse neonatal outcomes, including lower Apgar score, low blood sugar levels, high bilirubin, and needing extra oxygen. For the purpose of analysis, participants were followed through hospital discharge and chart review was performed through 6 weeks postpartum to monitor for readmissions.

Upon analysis, results indicated the primary outcome occurred among 34.0% of those randomized to nifedipine and 55.1% of those randomized to placebo (Relative risk [RR], 0.62 [95% CI, 0.39-0.97]), with a number needed to treat to prevent receipt of acute hypertension treatment of 4.7 (95% CI, 2.5-44.3). Further analysis indicated fewer individuals in the nifedipine group required cesarean delivery (20.8% vs 34.7%; RR, 0.60 [95% CI, 0.31-1.15]) and the rate of neonatal ICU admissions (29.1% vs 47.1%; RR 0.62 [95% CI, 0.37-1.02]) was lower with nifedipine compared with placebo therapy. Investigators noted analysis of the composite of adverse neonatal outcomes suggested rates were similar between study groups (35.8% vs 41.2%; RR, 0.83 [95% CI, 0.51-1.37]).

This study, “Trial of Intrapartum Extended-Release Nifedipine to Prevent Severe Hypertension Among Pregnant Individuals With Preeclampsia With Severe Features,” was published in Hypertension.