title: Elective cervical cerclage for prevention of preterm birth: a systematic review.
abstract: BACKGROUND
  Elective cervical cerclage has been purported to prevent spontaneous preterm birth. We present a systematic review to determine the effectiveness of cervical cerclage in preventing spontaneous preterm birth before 34 weeks' gestation.
  
  
  METHODS
  Searches were conducted in MEDLINE, EMBASE, Cochrane Library, and Science Citation Index to identify randomized trials published between 1966 and 2002. All randomized trials that evaluated the effectiveness of elective cerclage compared with no cerclage in women who were at risk of preterm birth before 34 weeks' gestation were included for analysis. Quality assessment and data extraction were performed in duplicate.
  
  
  RESULTS
  There were seven relevant trials, comprising 2354 women. Meta-analysis was inappropriate because of large differences in the quality of the studies. However, in the largest single trial of good quality, cerclage was shown to prevent birth before 34 weeks' gestation. In this single study the reported number to be treated to prevent one additional preterm birth before 34 weeks was 24 women (95% CI: 10-61). The results of other trials were consistent with the finding of the largest trial. Data on complications were sparse and inconclusive.
  
  
  CONCLUSIONS
  Our systematic review shows that elective cervical cerclage has a significant effect in preventing spontaneous preterm birth before 34 weeks' gestation. Further research should focus on identification and quantification of possible complications, and of risk factors and tests that identify high-risk women who would benefit most from cerclage.
authors.affiliation: Horten Centre, University of Zurich, Zurich, Switzerland. lucas.bachmann@evimed.ch
authors.forename: Lucas M
authors.initials: LM
authors.lastname: Bachmann
authors.forename: Aravinthan
authors.initials: A
authors.lastname: Coomarasamy
authors.forename: Honest
authors.initials: H
authors.lastname: Honest
authors.forename: Khalid S
authors.initials: KS
authors.lastname: Khan
mesh_terms: D023802:Cerclage, Cervical; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D015201:Meta-Analysis as Topic; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018566:Pregnancy, High-Risk; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D002581:Uterine Cervical Incompetence / Q000601:surgery*