Latency Antibiotics in Preterm Prelabor Rupture of Membranes: A Comparison of Azithromycin Regimens.

Background: Treatment with antibiotics at the time of preterm prelabor rupture of membranes (PPROM) has been shown to prolong pregnancy. Due to the recurrent shortage of erythromycin, azithromycin has been substituted in the traditional regimen; however, there are little data on optimal dosing.

Objective: The objective of this study was to determine whether there is a difference in latency from onset of PPROM to delivery in patients who received a single dose of azithromycin compared with a 5-day course.

Methods: This was a single-center, multisite, retrospective, IRB approved analysis of patients admitted with a diagnosis of PPROM. Patients were included if rupture occurred between 22 0/7 and 33 6/7 weeks of gestation and received either a single dose or a 5-day course of azithromycin along with a beta lactam.

Results: A total of 376 patients were reviewed with 296 patients included in the final analysis. There was no statistical difference in the primary outcome of latency days in patients who received the 5-day versus the single-dose course (4 vs 5 days, P = 0.641). There was a significantly higher rate of histologic chorioamnionitis in the single-dose course of azithromycin (46.4% vs 62.6%, P = 0.006).

Conclusions and relevance: There was no difference in latency for patients who received a 5-day course of azithromycin versus a single dose for the treatment of PPROM. A higher rate of histologic chorioamnionitis was observed in those who received the single-day course. Prospective follow-up studies are needed to confirm these findings.