title: Comparison between sonographic cervical length and Bishop score in preinduction cervical assessment: a randomized trial.
abstract: OBJECTIVE
  To compare sonographically measured cervical length with the Bishop score in determining the requirement for prostaglandin administration for preinduction cervical ripening in nulliparae at term.
  
  
  METHODS
  One hundred and fifty-four women with singleton pregnancies at term who were scheduled for induction of labor were randomly assigned to receive prostaglandin for preinduction cervical ripening based on the Bishop score or sonographic cervical length. A cervix unfavorable for treatment with prostaglandin for preinduction cervical ripening was defined as having either a Bishop score of ≤ 4 or a cervical length of ≥ 28 mm. The primary outcome measures were induction success (defined as an ability to achieve the active phase of labor) and the percentage of patients treated with prostaglandin for preinduction cervical ripening.
  
  
  RESULTS
  The two groups were similar with respect to maternal demographics, gestational age, cervical length, and Bishop score. The rates of induction success and Cesarean delivery, the interval to active phase of labor, and the interval to delivery were also similar in the two groups. However, in the transvaginal ultrasound group (n = 77), prostaglandin was administered to only 36% of the nulliparae compared with 75% of those in the Bishop score group (n = 77) (P < 0.0001).
  
  
  CONCLUSIONS
  In comparison with the Bishop score, the use of sonographic cervical length for assessing the cervix prior to induction of labor can reduce the need for prostaglandin administration by approximately 50% without adversely affecting the outcome of induction in nulliparae at term if the cut-off values used are a Bishop score of ≤ 4 and a cervical length of ≥ 28 mm.
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnamsi, Korea. pkh0419@snubh.org
authors.forename: K H
authors.initials: KH
authors.lastname: Park
authors.forename: S N
authors.initials: SN
authors.lastname: Kim
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.forename: E H
authors.initials: EH
authors.lastname: Jeong
authors.forename: H J
authors.initials: HJ
authors.lastname: Jung
authors.forename: K J
authors.initials: KJ
authors.lastname: Oh
mesh_terms: D000328:Adult; D054791:Cervical Length Measurement / Q000187:drug effects / Q000379:methods*; D020070:Cervical Ripening / Q000187:drug effects / Q000502:physiology*; D002584:Cervix Uteri / Q000000981:diagnostic imaging* / Q000187:drug effects; D003657:Decision Making; D036861:Delivery, Obstetric / Q000379:methods; D005260:Female; D006801:Humans; D007751:Labor, Induced; D010298:Parity; D011247:Pregnancy; D011453:Prostaglandins / Q000008:administration & dosage*; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014621:Vagina / Q000000981:diagnostic imaging* / Q000187:drug effects
chemical_list: D011453:Prostaglandins