Pregnancy Outcomes of Nifedipine Compared With Labetalol for Oral Treatment of Mild Chronic Hypertension
Authors: Sanusi Ayodeji A. , Leach Justin , Boggess Kim , Dugoff Lorraine , Sibai Baha , Lawrence Kirsten , Hughes Brenna L. , Bell Joseph , Aagaard Kjersti , Edwards Rodney K. , Gibson Kelly S. , Haas David M. , Plante Lauren , Metz Torri D. , Casey Brian , Esplin Sean , Longo Sherri , Hoffman Matthew K. , Saade George R. , Hoppe Kara K. , Foroutan Janelle , Tuuli Methodius , Owens Michelle Y. , Simhan Hyagriv N. , Frey Heather , Rosen Todd , Palatnik Anna , Baker Susan , August Phyllis , Reddy Uma M. , Su Emily J. , Krishna Iris , Nguyen Nguyet A. , Norton Mary E. , Skupski Daniel , El-Sayed Yasser Y. , Ogunyemi Dotun , Galis Zorina S. , Harper Lorie , Ambalavanan Namasivayam , Geller Nancy L. , Kuo Hui-Chien , Sinkey Rachel G. , Librizzi Ronald , Pereira Leonardo , Magann Everett F. , Habli Mounira , Williams Shauna , Mari Giancarlo , Pridjian Gabriella , McKenna David S. , Parrish Marc , Eugene Chang  , Osmundson Sarah , Quinones JoAnne , Szychowski Jeff M. , Tita Alan T. N. 
Published: May 2024

OBJECTIVE:
To evaluate maternal and neonatal outcomes by type of antihypertensive used in participants of the CHAP (Chronic Hypertension in Pregnancy) trial.

METHODS:
We conducted a planned secondary analysis of CHAP, an open-label, multicenter, randomized trial of antihypertensive treatment compared with standard care (no treatment unless severe hypertension developed) in pregnant patients with mild chronic hypertension (blood pressure 140–159/90–104 mm Hg before 20 weeks of gestation) and singleton pregnancies. We performed three comparisons based on medications prescribed at enrollment: labetalol compared with standard care, nifedipine compared with standard care, and labetalol compared with nifedipine. Although active compared with standard care groups were randomized, medication assignment within the active treatment group was not random but based on clinician or patient preference. The primary outcome was the occurrence of superimposed preeclampsia with severe features, preterm birth before 35 weeks of gestation, placental abruption, or fetal or neonatal death. The key secondary outcome was small for gestational age (SGA) neonates. We also compared medication adverse effects between groups. Relative risks (RRs) and 95% CIs were estimated with log binomial regression to adjust for confounding.

RESULTS:
Of 2,292 participants analyzed, 720 (31.4%) received labetalol, 417 (18.2%) received nifedipine, and 1,155 (50.4%) received no treatment. The mean gestational age at enrollment was 10.5±3.7 weeks; nearly half of participants (47.5%) identified as non-Hispanic Black; and 44.5% used aspirin. The primary outcome occurred in 217 (30.1%), 130 (31.2%), and 427 (37.0%) in the labetalol, nifedipine, and standard care groups, respectively. Risk of the primary outcome was lower among those receiving treatment (labetalol use vs standard adjusted RR 0.82, 95% CI, 0.72–0.94; nifedipine use vs standard adjusted RR 0.84, 95% CI, 0.71–0.99), but there was no significant difference in risk when labetalol was compared with nifedipine (adjusted RR 0.98, 95% CI, 0.82–1.18). There were no significant differences in SGA or serious adverse events between participants receiving labetalol and those receiving nifedipine.

CONCLUSION:
No significant differences in predetermined maternal or neonatal outcomes were detected on the basis of the use of labetalol or nifedipine for treatment of chronic hypertension in pregnancy.

CLINICAL TRIAL REGISTRATION:

ClinicalTrials.gov, NCT02299414.