Azithromycin for Cerclage Prophylaxis

The overall objective of this prospective two-arm randomized study is to (1) randomize subjects to azithromycin surgical prophylaxis versus placebo, plus the standard of care - cefazolin, at the time of cerclage placement and evaluate the impact on preterm delivery \<37 weeks, \<34 weeks and \<28 weeks and (2) determine the prevalence of mycoplasma species in cerclage patients. Pregnant women who are candidates for cervical cerclage will be enrolled and divided into two cohorts (approximately 40 per group): (1) Cerclage + Azithromycin prophylaxis (treatment group), and (2) Cerclage without azithromycin prophylaxis (control group). Both groups will receive otherwise usual care.