title: Use of macrolides during pregnancy and the risk of birth defects: a population-based study.
abstract: OBJECTIVE
  Macrolides have been linked to the occurrence of congenital heart defects, but findings are inconsistent. We therefore aimed to estimate the risk of major congenital malformations (MCMs) after fetal exposure to macrolides, focusing on cardiac malformations.
  
  
  METHODS
  From the Quebec Pregnancy Cohort (1998-2008), women exposed to a macrolide or penicillin in the first trimester and unexposed women were studied. There were 135 859 pregnancies included; 914 were exposed to azithromycin, 734 to erythromycin, 686 to clarithromycin, and 9106 to penicillin during the first trimester. Cases of MCMs were identified within the first year of life.
  
  
  RESULTS
  After adjusting for potential confounders, azithromycin (RR = 1.19, 95%CI: 0.98, 1.44; 120 exposed cases), erythromycin (RR = 0.96, 95%CI: 0.74, 1.24; 66 exposed cases) and clarithromycin use (RR = 1.12, 95%CI: 0.99, 1.42; 79 exposed cases) during the first trimester of pregnancy were not statistically significantly associated with the risk of MCMs; no associations were observed for cardiac malformations.
  
  
  CONCLUSIONS
  First trimester exposure to any of the macrolides was not associated with an increased risk of overall MCMs or cardiac malformations specifically.
authors.affiliation: Research Center, CHU Ste-Justine, Montreal, Quebec, Canada.|Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Anick
authors.initials: A
authors.lastname: Bérard
authors.affiliation: Research Center, CHU Ste-Justine, Montreal, Quebec, Canada.
authors.forename: Odile
authors.initials: O
authors.lastname: Sheehy
authors.affiliation: Research Center, CHU Ste-Justine, Montreal, Quebec, Canada.|Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Jin-Ping
authors.initials: JP
authors.lastname: Zhao
authors.affiliation: PharmacoEpidemiology and Drug Safety Research Group, School of Pharmacy, University of Oslo, Norway.
authors.forename: Hedvig
authors.initials: H
authors.lastname: Nordeng
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D017963:Azithromycin / Q000009:adverse effects; D017291:Clarithromycin / Q000009:adverse effects; D015331:Cohort Studies; D004917:Erythromycin / Q000009:adverse effects; D005260:Female; D006330:Heart Defects, Congenital / Q000139:chemically induced / Q000453:epidemiology*; D006801:Humans; D007231:Infant, Newborn; D018942:Macrolides / Q000009:adverse effects*; D010406:Penicillins / Q000009:adverse effects; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000209:etiology; D011792:Quebec / Q000453:epidemiology; D012042:Registries; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides; D010406:Penicillins; D004917:Erythromycin; D017963:Azithromycin; D017291:Clarithromycin
keywords: Quebec Pregnancy Cohort; azithromycin; cardiac malformations; erythromycin; macrolides; major malformations; pharmacoepidemiology; pregnancy