title: Cervical ripening with the balloon catheter and the risk of subsequent preterm birth.
abstract: OBJECTIVE
  To examine the risk of subsequent preterm birth after cervical ripening using a balloon catheter.
  
  
  METHODS
  A retrospective study was held at a university teaching hospital between January 2007 and June 2013. The study group included women who underwent cervical ripening using a balloon (single or double) catheter in the previous pregnancy followed by a subsequent singleton delivery (balloon catheter group). Two control groups were included. The first was similar to the study group except that ripening was achieved in the previous pregnancy with vaginal prostaglandin E2 (PGE2 group). The second control group had a previous pregnancy that resulted in spontaneous onset of labor at term (unexposed group). The primary outcome was the incidence of spontaneous preterm birth (before 37 weeks) in the index pregnancy.
  
  
  RESULTS
  Overall, 558 women were included; each group consisted of 186 women. The incidence of spontaneous preterm birth in the index pregnancy did not differ between the groups (0.5, 1.6 and 2.7% in the balloon catheter, PGE2 and in the unexposed groups, respectively, P=0.31). Among the balloon catheter group, 58 (31.2%) women had the ripening performed with a single-balloon catheter and 128 (68.8%) women with a double-balloon catheter. The rate of the spontaneous preterm birth in the index pregnancy did not differ between the two groups (P=1.0).
  
  
  CONCLUSIONS
  Cervical ripening with a balloon catheter does not increase the rate of subsequent spontaneous preterm birth.
authors.affiliation: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.|Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: N
authors.initials: N
authors.lastname: Zafran
authors.affiliation: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.|Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: G
authors.initials: G
authors.lastname: Garmi
authors.affiliation: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Zuarez-Easton
authors.affiliation: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.|Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Z
authors.initials: Z
authors.lastname: Nachum
authors.affiliation: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.|Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Salim
mesh_terms: D000282:Administration, Intravaginal; D000328:Adult; D002404:Catheterization / Q000379:methods*; D020070:Cervical Ripening; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D007231:Infant, Newborn; D007557:Israel; D007751:Labor, Induced / Q000379:methods*; D016015:Logistic Models; D015999:Multivariate Analysis; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult