Nifedipine During Labor Controls BP in Severe Preeclampsia

Megan Brooks

October 05, 2022

Women with preeclampsia with severe features benefit from treatment with oral nifedipine during labor and delivery, results of a randomized controlled trial suggest.

The study showed that intrapartum administration of extended-release oral nifedipine was safe and reduced the need for acute intravenous (IV) or immediate-release oral hypertensive therapy. There was a trend toward fewer cesarean deliveries and less need for neonatal intensive care.

Dr Erin Cleary

The results suggest that providers "consider initiating long-acting nifedipine every 24 hours for individuals with preeclampsia with severe features who are undergoing induction of labor," Erin M. Cleary, MD, with the Ohio State University, Columbus, told | Medscape Cardiology.

"There is no need to wait until patients require one or more doses of acute [antihypertensive] therapy before starting long-acting nifedipine, as long as they otherwise meet criteria for preeclampsia with severe features," Cleary said.

The study was published online October 3 in Hypertension.

Clear Benefits for Mom and Baby

Preeclampsia complicates up to 8% of pregnancies and often leads to significant maternal and perinatal morbidity.

"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," Cleary explains in a news release.

In a randomized, triple-blind, placebo-controlled study, the researchers assessed whether treatment with long-acting nifedipine could prevent severe hypertension in women with a singleton or twin gestation and preeclampsia with severe features, as defined according to American College of Obstetrics and Gynecology criteria.

During induction of labor between 22 and 41 weeks' gestation, 55 women were assigned to 30-mg oral extended-release nifedipine, and 55 received matching placebo, administered every 24 hours until delivery.

The primary outcome was receipt of one or more doses of acute hypertension therapy for blood pressure of at least 160/110 mm Hg that was sustained for 10 minutes or longer.

The primary outcome occurred in significantly fewer women in the nifedipine group than in the placebo group (34% vs 55%; relative risk [RR], 0.62; 95% CI, 0.39 – 0.97; number needed to treat, 4.7).

Fewer women in the nifedipine group than in the placebo group required cesarean delivery, although this difference did not meet statistical significance (21% vs 35%; RR, 0.60; 95% CI, 0.31 – 1.15).

There was no between-group difference in the rate of hypotensive episodes, including symptomatic hypotension requiring phenylephrine for pressure support following neuraxial anesthesia (9.4% vs 8.2%; RR, 1.15; 95% CI, 0.33 – 4.06).

After delivery, there was no difference in the rate of persistently severe blood pressure that required acute therapy and maintenance therapy at time of discharge home.

Birthweight and rates of births of neonates who were small for gestational age were similar in the two groups. There was a trend for decreased rates of neonatal intensive care unit admission among infants born to mothers who received nifedipine (29% vs 47%; RR, 0.62; 95% CI, 0.37 – 1.02).

The neonatal composite outcome was also similar between the nifedipine group and the placebo group (36% vs 41%; RR, 0.83; 95% CI, 0.51 – 1.37). The composite outcome included Apgar score of <7 at 5 minutes, hyperbilirubinemia requiring phototherapy, hypoglycemia requiring intravenous therapy, or supplemental oxygen therapy beyond the first 24 hours of life.

"Our findings support the growing trend in more active management of hypertension in pregnancy with daily maintenance medications," Cleary and colleagues note in their article.

"Even in the absence of preeclampsia, emerging research suggests pregnant individuals may benefit from initiating and titrating antihypertensive therapy at goals similar to the non-obstetric population," they add.

Potentially Practice Changing

Reached for comment, Vesna Garovic, MD, PhD, with Mayo Clinic, Rochester, Minnesota, said that this is an "important initial paper to start a very important conversation about blood pressure treatment goals in preeclampsia."

Garovic noted that for chronic hypertension in pregnancy, the blood pressure treatment goal is now ≤140/90 mm Hg.

"However, this does not apply to preeclampsia, where quite high blood pressures, such 160/110 mm Hg or higher, are still allowed before treatment is considered," Garovic told | Medscape Cardiology.

"This study shows that as soon as you reach that level, treatment with oral nifedipine should be initiated and that timely initiation of oral nifedipine may optimize blood pressure control and decrease the need for intravenous therapy subsequently, and that has good effects on the mother without adversely affecting the baby," Garovic said.

"This is potentially practice changing," Garovic added. "But the elephant in the room is the question of why we are waiting for blood pressure to reach such dangerous levels before initiating treatment, and whether initiating treatment at a blood pressure of 140/90 or higher may prevent blood pressure reaching these high levels and women developing complications that are the consequence of severe hypertension."

The study was funded by the Ohio State University's Department of Obstetrics and Gynecology. Cleary and Garovic have disclosed no relevant financial relationships.

Hypertension. Published online October 3, 2022. Abstract

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