title: Impact of Azithromycin on Pregnancy Prolongation in Women at Risk of Preterm Labor: A Time-to-Event Analysis.
abstract: Since 2006, the empiric use of azithromycin in women at risk of premature birth has become prevalent in our institution without any evidence of its efficacy. Although antibiotics can prolong pregnancy in preterm prolonged rupture of membranes, no published data are available for women with intact membranes.
  
  
  
  To describe the purpose of adding azithromycin to the usual treatments (cerclage, tocolysis, rest, etc.) to prolong pregnancy in women with intact membranes who are at risk of or already in preterm labour.
  
  
  
  A retrospective observational cohort study was done at a Mother-Child University Hospital Centre. Patients admitted to obstetric ward who received azithromycin between January 1st, 2006 and August 1st, 2010 were included. A total of 127 exposed women were matched to 127 controls through medical records and pharmacy software. A time-to-event analysis was done to compare gestational age at the time of the recorded composite event (delivery, or rupture of membranes, or second intervention to prolong pregnancy). To compare proportions of composite event at different time points, χ2tests were used.
  
  
  
  Patients who received azithromycin had a more severe condition at presentation. Once adjusted for confounding factors, prolongation of pregnancy (HR =1.049; CI 95%: 0.774-1.421 [p=0.758]) and gestational age at the event (HR=1.200; CI 95%: 0.894-1.609 [p=0.225]) did not differ between the groups. The proportions of women with an event ≥7 days post-diagnosis or ≥37 gestational weeks were similar.
  
  
  
  Azithromycin was added to medical therapy in a more at-risk population and no clear benefit was measured.
authors: Department of Pharmacy, Sainte-Justine UHC.
authors: Isabelle
authors: I
authors: Goyer
authors: Department of Pharmacy, Sainte-Justine UHC.
authors: Gabrielle
authors: G
authors: Ferland
authors: Department of Pharmacy, McGill UHC.
authors: Ni
authors: N
authors: Ruo
authors: Department of Pharmacy, Sainte-Justine UHC.
authors: Caroline
authors: C
authors: Morin
authors: Department of Pharmacy, Sainte-Justine UHC.
authors: Marie-Sophie
authors: MS
authors: Brochet
authors: Department of Maternal Fetal Medicine Sainte-Justine UHC.|Faculty of Medicine, University of Montreal.
authors: Lucie
authors: L
authors: Morin
authors: Department of Pharmacy, Sainte-Justine UHC.|Faculty of Pharmacy, University of Montreal.
authors: Ema
authors: E
authors: Ferreira
mesh_terms: D000328:Adult; D017963:Azithromycin / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors
chemical_list: D017963:Azithromycin
keywords: antibiotic; azithromycin; pregnancy; premature birth; preterm birth; preterm labour