Erythromycin Versus Azithromycin for Preterm Prelabor Rupture of Membranes

Preterm pre-labor rupture of membranes (PPROM) complicates 3% of pregnancies and accounts for one-fourth to one-third of preterm births. PPROM is associated with significant maternal and neonatal morbidities, including chorioamnionitis, endometritis, neonatal sepsis, prematurity-related pathologies. In the absence of labor or indication for immediate delivery, patients who present at less than 34 weeks gestational age are treated with antibiotics to prolong pregnancy until 34 weeks when the risks of prematurity are decreased. Based on randomized trials, both the American College of Obstetrics and Gynecology (ACOG) and the Society of Maternal Fetal Medicine (SMFM) recommend IV ampicillin and IV erythromycin for 2 days, followed by an oral regimen of amoxicillin and erythromycin for 5 days. Due to the recent limited availability of erythromycin, azithromycin has been used a substitute. There have been observational studies showing no difference in duration of pregnancy between azithromycin and erythromycin, however no randomized controlled trial has been carried out to our knowledge. This study performs a cluster randomized controlled trial to examine the efficacy of azithromycin versus erythromycin as a component of the "latency antibiotics" used to prolong pregnancy in PPROM patients.

Inclusion criteria

• Pregnancy at 22 weeks 0 days to 32 weeks 6 days of gestation.
• Rupture of membranes confirmed by biochemical testing.
• Membrane rupture within the past 36 hours.
• Cervical dilation 3 cm or less and 4 or fewer contractions within 60-minutes at the time of admission.
• Age ≥18 and <50 years.

Exclusion criteria

• Non-reassuring fetal heart tracing, vaginal bleeding, chorioamnionitis or any indication for delivery at admission.
• Allergy to penicillin, erythromycin, or azithromycin.
• Multiple gestations.