Comparative Effectiveness of Azithromycin versus Erythromycin for Latency Prolongation in Preterm Prelabor Rupture of Membranes < 34 Weeks of Gestation.

Objective: Preterm prelabor rupture of membranes (PPROM) is a major contributor to preterm birth and neonatal morbidity. Although azithromycin is increasingly used as an alternative to erythromycin for latency antibiotic therapy, comparative data remain limited. This study evaluated whether azithromycin is associated with latency duration and maternal-neonatal outcomes comparable to those of erythromycin in pregnancies complicated by PPROM before 34 weeks of gestation. Methods: A retrospective cohort study was conducted at a tertiary referral hospital by reviewing medical records from January 2011 through December 2024. Pregnant women with PPROM at 24 to <34 weeks of gestation who completed latency antibiotic regimens were included and categorized into azithromycin or erythromycin groups. The primary outcome was latency period (time from membrane rupture to delivery). Secondary outcomes included maternal infectious complications and neonatal morbidity and mortality. Multivariable logistic regression was performed to adjust for baseline differences between groups. Results: A total of 720 participants were included (56 azithromycin; 664 erythromycin). Baseline characteristics were generally comparable, although maternal age, monthly income, and previous PPROM differed between groups. Median latency duration did not differ significantly between azithromycin and erythromycin overall (3.70 vs 3.23 days; Conclusion: Azithromycin was associated with latency duration and maternal-neonatal outcomes comparable to those of erythromycin and represents a practical alternative regimen for PPROM management. Prospective studies are warranted to confirm these findings.