Extended Azithromycin Treatment in Prelabor Rupture of Membranes

Multiple randomized trials have shown that antibiotic treatment for preterm prelabor rupture of membranes (PPROM) increases pregnancy latency and decreases maternal and neonatal morbidity. However, the optimal dosing schedule for azithromycin in PPROM is not fully understood. This pilot study will assess the feasibility of a non-blinded, randomized-controlled trial comparing maternal and neonatal outcomes between the standard PPROM antibiotic regimen and the standard regimen with extended azithromycin therapy in participants with periviable and extremely preterm PPROM between 22- and 28-weeks gestational age. Preliminary data on pregnancy latency, maternal morbidity, and neonatal outcomes will also be collected. Findings from this feasibility study will inform the design of a future, powered study.

The investigators hypothesize that extended azithromycin therapy may be associated with longer pregnancy latency and decreased rates of maternal and neonatal morbidity compared to standard therapy. This hypothesis is exploratory, and the present feasibility study is not powered to test a hypothesis.

The primary objective is to evaluate the feasibility of conducting a non-blinded, randomized controlled trial of extended azithromycin therapy in participants with periviable and extremely preterm prelabor rupture of membranes (PPROM) who desire expectant management between 22 and 28 weeks gestational age. Specifically, we aim to assess feasibility metrics including recruitment and consent rates, randomization procedures, adherence to the study protocol, and completeness of follow-up.

The secondary objectives of this pilot study are to estimate the variability (standard deviation) of pregnancy latency in this population to inform sample-size calculations for a future definitive trial. The investigators will also collect preliminary data on maternal outcomes (e.g., rates of intra-amniotic infection, endometritis, and placental abruption) and neonatal outcomes (gestational age at delivery, NICU admission, morbidity) for planning purposes. Additionally, the investigators will review placental pathology reports to identify the stage/grade of chorioamnionitis per the Amsterdam criteria. The investigators will obtain an initial estimate of the effect of extended azithromycin on pregnancy latency, recognizing that this pilot study is not powered to detect clinically meaningful differences.

Inclusion criteria

• Singleton gestation
• Gestational age at time of PPROM between 22w0d and 28w0d
• Opting for expectant management in the inpatient setting after completion of a maternal-fetal medicine and neonatology consultation (per standard of care)
• Remain pregnant 48 hours after presentation.
• Patients who receive betamethasone, magnesium therapy, and/or a limited course of tocolysis (through the betamethasone window) will be included.
• Pregnant patients below the age of 18 are eligible.

Exclusion criteria

• Contraindications to expectant management (clinical intra-amniotic infection, active preterm labor, or acute placental abruption)
• Lethal congenital defects
• Multiple gestation
• Ongoing alternative antibiotic treatment
• Known hypersensitivity to azithromycin, erythromycin, any macrolide or ketolide antibiotic
• History of cholestatic jaundice/hepatic dysfunction associated with prior use of azithromycin
• Known prolongation of QT interval
• History of torsades de pointes
• Congenital long QT syndrome
• Bradyarrhythmia
• Decompensated heart failure
• Drugs known to significantly prolong the QT interval including Class 1A and Class III antiarrhythmic agents
• Impaired hepatic function
• GFR<10 mL/min
• Diagnosis of myasthenia gravis