Postpartum Readmission Lower With Nifedipine Vs Labetalol

Postpartum patients with hypertension who were prescribed nifedipine at discharge had an 88% lower readmission rate than those prescribed labetalol, according to a randomized controlled trial presented at the annual meeting of the Society of Maternal-Fetal Medicine.

Only 1.2% of postpartum patients taking nifedipine were readmitted compared with 8.1% of those taking labetalol (adjusted odds ratio [aOR] = 0.12; 95% CI, 0.026-0.57), according to the data Todd Lovgren, MD, of Nebraska Methodist Women’s Hospital and Perinatal Center in Omaha, Nebraska, presented at the meeting. The number needed to treat to avoid one readmission was 14.6.

“Nifedipine should be the first-line agent for management of postpartum hypertension,” Lovgren told attendees, and now it will be important to identify other antihypertensives for the postpartum period.

“The implication for this in the United States is, if we move labetalol to a second- or third-line agent, and if even half of that 90% reduction in readmission correlated with reduction of maternal mortality, it could move the needle on maternal mortality in the US,” Lovgren told Medscape Medical News. 

“We’ve been neglecting women for decades with the thought process that delivery cures them of preeclampsia and cures them of hypertension,” Lovgren said. Of the 6% of maternal deaths caused solely by preeclampsia, about two thirds occur postpartum, he said. “Yet, we’ve really done no research postpartum.” 

A quality improvement plan at Lovgren’s hospital suggested that having a normal blood pressure at discharge and prescribing antihypertensive medication at discharge would decrease the risk for readmission.

Instead, however, an observational study revealed that hypertension prior to discharge even with medication increased risk for readmission, and a prescription for medication at discharge did not affect readmission risk. Since medication, unspecified, did not seem to mitigate risk for the group as whole, the team suspected that nifedipine and labetalol may have different readmission risks.

In their next observational study, Lovgren compared readmission rates for these medications against no medication and found a significantly higher risk for readmission with labetalol (aOR, 1.94) and lower risk with nifedipine (aOR, 0.35). 

For the current randomized controlled trial, the researchers included 323 patients aged > 18 years who had two hypertensive blood pressure readings at least 4 hours apart and did not have bradycardia or tachycardia. Then 161 patients were randomly assigned to receive 200 mg of labetalol every 8 hours and 162 patients received 30 mg of nifedipine twice daily.

The primary outcome of readmission within 6 weeks of delivery due to complications of hypertension included myocardial infarction, cerebrovascular accident, congestive heart failure, HELLP syndrome, eclampsia, or preeclampsia with severe features (at least 160 mm Hg systolic or 110 mm Hg diastolic). 

Patients were an average 31 years old and mostly non-Hispanic White individuals (90.1%) with similar body mass index (BMI; 35.3 with labetalol and 37 with nifedipine). The nifedipine group delivered at a median 37 weeks while the labetalol group delivered at a median 38 weeks. Most had private insurance (87%-88%), and most had a vaginal delivery (60%-61%). Patients in the labetalol group had significantly more chronic hypertension (10.6% vs 4.3%, P = .033), but rates of preeclampsia, severe hypertension, or other medications were not significantly different.

The findings support those of a systematic review just published in this month’s issue of O&G Open that included three retrospective cohort studies and two randomized controlled trials comparing patients prescribed nifedipine or labetalol at postpartum discharge. In 30,950 postpartum patients with hypertension, 39.6% of patients were prescribed nifedipine and 60.5% were prescribed labetalol between January 2006 and December 2022.

The readmission rate for postpartum hypertension was 2.4% among patients receiving nifedipine compared with 6.5% in those receiving labetalol. “In addition, most patients treated with a calcium channel blocker had a shorter time to achieve blood pressure control than those treated with labetalol,” Courtney Y. Wang, MD, Baylor College of Medicine in Houston, Texas, and her colleagues reported.

Diana S. Wolfe, MD, MPH, the obstetric director of Maternal Fetal Medicine Cardiology Joint Program and a professor at Montefiore Einstein, told Medscape Medical News, “Procardia [nifedipine] is already the number one choice,” but “there are some patients who have side effects, such as headache and dizziness.”

She said that home blood pressure monitoring after delivery is important in the first 12 weeks “as there are immediate physiologic changes leading to less need for blood pressure control.” Wolfe, who was not involved in the study, also noted that confounding factors, such as other comorbidities, compliance, BMI, and access to care, can dictate medication options.

Though a strength of the study is its generalizability, the study used surrogate measures — discharge medication instead of assessing actual adherence and readmission rates instead of mortality — and was prematurely closed because it exceeded the predetermined Data Safety Monitoring Board safety threshold.

Lovgren said he hopes the findings of his study motivate other researchers to really investigate all the other different agents they can consider for postpartum management of hypertension. 

“I think the next 5 years is going to absolutely revolutionize postpartum care,” he said. “I’m hoping in 10 years that I can look at a graph and I can see where maternal mortality got better in our country in the 5 years after 2025 as we start taking better care of women in the postpartum period.” 

The research was funded by Methodist Hospital Foundation. Lovgren and Wolfe had no disclosures. The authors of the systematic review had no disclosures.

Tara Haelle is a science/health journalist based in Dallas, Texas.