(674) Comparison of pregnancy latency in preterm preeclampsia with oral labetalol versus extended-release nifedipine

To compare pregnancy latency achieved with oral labetalol versus extended-release nifedipine during expectant management of preterm preeclampsia with severe features (PEC-SF).

Study Design:

This is a retrospective cohort study of patients initiated on antihypertensive therapy with oral labetalol or extended-release nifedipine during admission for expectant management of PEC-SF < 34 weeks between 1/2013 and 4/2022. Those on antihypertensive therapy prior to admission or with another indication for delivery < 34 weeks were excluded (monochorionic-monoamniotic twins, higher order multiples, absent or reversed umbilical artery Dopplers). Pregnancy latency (from oral agent initiation to delivery decision) was compared between groups. Secondary outcomes included need for initial agent dose uptitration, addition of second oral agent, acute antihypertensive therapy, and delivery for refractory hypertension. Linear and modified Poisson regression models were used to estimate adjusted mean differences (AMD) with 95% confidence intervals.


Results:

The cohort included 78 patients (Table 1). Comparing those initiated on labetalol versus extended-release nifedipine (Table 2), there was no difference in latency (6.2 (7.5) vs 5.4 (7.4) days, AMD 1.1 days, 95% CI [-2.1, 4.4]), nor in the proportion of patients achieving 1 week latency (25.0% vs 23.8%, respectively, AMD 2.9%, 95% CI [-16.5, 22.3]). Those initiated on labetalol were less likely to require a second agent (16.7% vs 38.1% for nifedipine, AMD -18.4, 95% CI [-37.3, 0.5]). There were no differences in need for initial agent uptitration, acute antihypertensive therapy, or delivery for refractory hypertension.


Conclusion:

There was no difference in pregnancy latency among patients with PEC-SF initiated on oral labetalol versus extended-release nifedipine. Patients on labetalol may be less likely to require a second antihypertensive agent, but comparative outcome estimates may be limited by small cohort size. Further investigations with a larger cohort should be performed to evaluate for any relative advantages of the two oral agents.