127 Gestational latency associated with erythromycin vs azithromycin in patients admitted with PPROM

Abstract

Administration of antibiotics after preterm premature rupture of membranes (PPROM) has been shown to increase gestational latency. While the original studies included ampicillin and erythromycin, shortages of erythromycin have led to use of azithromycin in its stead. We sought to evaluate whether the use of azithromycin compared to erythromycin, is associated with changes in perinatal outcomes including gestational latency. This retrospective cohort study included women with singleton gestations admitted to a quaternary center from 9/2014 to 3/2020 with a diagnosis of PPROM between 23w0d and 33w5d. In 2017, the hospital’s policy universally changed from a 7-day course of erythromycin to one dose of oral azithromycin 1000mg. The primary outcome was gestational latency. Secondary outcomes included gestational age (GA) at delivery; chorioamnionitis; birthweight; 5-minute Apgar <7; respiratory distress syndrome; necrotizing enterocolitis; intraventricular hemorrhage; neonatal length of stay; and neonatal death. An a priori power analysis determined that a sample of 120 patients per group would identify a 2-day difference in gestational latency (with a power of 80% and an alpha of 0.05). Bivariable and multivariable analyses were performed. 280 patients met inclusion criteria. Patients receiving erythromycin had a higher frequency of prior spontaneous preterm birth (PTB) and presented at a later GA with PPROM (Table 1). No other differences were observed in patient characteristics. There were no differences in gestational latency between patients who received azithromycin compared to erythromycin in bivariable [10 (4-15) vs 8.5 (3-14) days, p=0.16) or multivariable analyses [adjusted β = 0.13 days (95% CI: -0.08-0.34 days) (Table 2). There were no statistically significant differences in secondary outcomes. There was no difference in gestational latency or incidence of adverse perinatal outcomes when comparing azithromycin to erythromycin. A single dose of azithromycin appears to be a reasonable substitute to erythromycin for gestational latency in the setting of PPROM.View Large Image Figure ViewerDownload Hi-res image Download (PPT)