Comparative Effectiveness and Safety of Labetalol Versus Nifedipine for Treatment of Chronic Hypertension During Pregnancy

Clinical guidelines recommend treatment of chronic hypertension during pregnancy, with either labetalol or nifedipine as the first-line medication. This study aimed to compare the effectiveness and safety of labetalol and nifedipine for the treatment of chronic hypertension during pregnancy. We used a target trial emulation approach to compare new users of labetalol with new users of nifedipine. We analyzed data from the U.S. Merative™ MarketScan® Commercial Database of insurance claims (2007-2022) for pregnant individuals with chronic hypertension and their infants. The effectiveness outcome was a composite of severe preeclampsia/eclampsia, medically indicated preterm birth, placental abruption, or stillbirth. The safety outcome was an infant born small for gestational age. We estimated risk ratios (RRs) and risk differences (RDs) with 95% CIs, adjusting for confounding with stabilized inverse probability of treatment weights. We studied 6,724 pregnant individuals with chronic hypertension who initiated either labetalol (n = 5,504, 82%) or nifedipine (n = 1,220, 18%) in pregnancy. The effectiveness outcome occurred in 42% in the labetalol group and 44% in the nifedipine group, with an adjusted RR of 1.03 (95% CI: 0.96-1.11) and an adjusted RD of 1.35 per 100 births (95% CI: -1.76 to 4.45). The safety outcome of small for gestational age occurred in 13% in the labetalol group and 12% in the nifedipine group, with an adjusted RR of 0.98 (95% CI: 0.82-1.16) and an adjusted RD of -0.26 per 100 births (95% CI: -2.33 to 1.81). This study suggests that labetalol and nifedipine have similar effectiveness and safety in treating chronic hypertension during pregnancy.