title: Is metronidazole teratogenic? A meta-analysis.
abstract: OBJECTIVE
  In order to assess whether the use of metronidazole during pregnancy is associated with a higher risk of congenital malformations, a meta-analysis was conducted.
  
  
  METHODS
  All epidemiological studies (cohort and case-control) which estimate risk of congenital malformations after exposure to metronidazole during early pregnancy were included in the meta-analysis. To obtain a summary odds ratio, the Mantel-Haenszel method was used. A test to verify absence of heterogeneity was also performed.
  
  
  RESULTS
  One unpublished case-control and four published cohort studies fulfilled the inclusion criteria and were not statistically heterogeneous. A summary odds ratio was calculated for metronidazole exposure during the first trimester: OR = 1.08, 95% CI: 0.90-1.29, heterogeneity test chi2 = 4.72, P = 0.32.
  
  
  CONCLUSIONS
  This meta-analysis did not find any relationship between metronidazole exposure during the first trimester of pregnancy and birth defects.
authors.affiliation: Instituto de Farmacoepidemiología, Universidad de Valladolid, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Caro-Patón
authors.forename: A
authors.initials: A
authors.lastname: Carvajal
authors.forename: I
authors.initials: I
authors.lastname: Martin de Diego
authors.forename: L H
authors.initials: LH
authors.lastname: Martin-Arias
authors.forename: A
authors.initials: A
authors.lastname: Alvarez Requejo
authors.forename: E
authors.initials: E
authors.lastname: Rodríguez Pinilla
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008795:Metronidazole / Q000009:adverse effects*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D011261:Pregnancy Trimester, First; D013030:Spain / Q000453:epidemiology; D013723:Teratogens / Q000633:toxicity*; D014247:Trichomonas Vaginitis / Q000188:drug therapy* / Q000453:epidemiology; D016585:Vaginosis, Bacterial / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D013723:Teratogens; D008795:Metronidazole