Purpose: Prophylactic antibiotics to prolong latency and reduce the risk of neonatal and maternal infections are used for preterm premature rupture of membranes. This study compared outcomes between two macrolides: roxithromycin given twice a day for a week and azithromycin, given as a single dose, which is more convenient.
Methods: Two local protocols were retrospectively compared: roxithromycin and ampicillin from July 2005 to May 2016, and azithromycin and ampicillin from May 2016 to May 2018. Inclusion criteria were singleton pregnancy, at 24-34 weeks of gestation upon admission with preterm premature rupture of membranes. Primary outcome was length of the latency period, defined as time from first antibiotic dose to 34 + 0 weeks, or spontaneous or indicated delivery prior to 34 + 0 weeks. Secondary outcomes were rates of chorioamnionitis, delivery mode, birth weight and Apgar scores.
Results: A total of 207 women met inclusion criteria, of whom, 173 received penicillin and roxithromycin and 34 received penicillin and azithromycin. Baseline characteristics were similar between groups. The latent period was longer in the azithromycin group than in the roxithromycin group (14.09 ± 14.2 days and 7.87 ± 10.2 days, respectively, P = 0.003). Rates of chorioamnionitis, cesarean deliveries, Apgar scores and birth weights were similar between the groups.
Conclusions: Azithromycin compared to roxithromycin results in a longer latency period in the setting of preterm premature rupture of membranes at 24-34 weeks of gestation. Given its more convenient regimen and our results, it seems justified to use azithromycin as the first-line treatment for patients with preterm premature rupture of membranes.
Keywords: Azithromycin; Latency period; Preterm premature rupture of membranes; Prophylactic antibiotics; Roxithromycin.