title: Second Trimester Cervical Length and Its Association with Vaginal Birth after Cesarean Delivery.
abstract: OBJECTIVE
  This study aims to evaluate the relationship between cervical length (CL) and trial of labor after cesarean (TOLAC) delivery.
  
  
  METHODS
  This retrospective cohort study evaluated second trimester CL and likelihood of successful TOLAC. Women undergoing TOLAC from January 2009 to December 2011 who underwent transvaginal ultrasound CL between 18(0/7) to 23(6/7) weeks gestation were included. The threshold for CL was assessed using a receiver operating characteristics curve, with ≥ 45 mm determined to be the optimal threshold. Women with CL < 45 mm were compared with women with CL ≥ 45 mm with respect to TOLAC. Multivariate analysis was used to assess the association of CL with TOLAC.
  
  
  RESULTS
  A total of 45 patients met inclusion criteria, 14 (31%) with a long CL (≥ 45 mm) and 31 (69%) with CL < 45 mm. Groups did not differ in demographics or factors predictive of vaginal birth after cesarean (VBAC) delivery. More women with CL < 45 mm had successful VBAC (81%) than women with long CL (43%, relative risk 1.9, p = 0.03). Prior vaginal delivery and CL < 45 mm were both significant predictors of VBAC (odds ratio 1.8 and 2.0, respectively).
  
  
  CONCLUSIONS
  CL < 45 mm is associated with VBAC.
authors.affiliation: Department of Obstetrics and Gynecology, Main Line Health Systems, Wynnewood, Pennsylvania.
authors.forename: Sara S
authors.initials: SS
authors.lastname: Nicholas
authors.affiliation: Department of Obstetrics and Gynecology, Virginia Hospital Center, Arlington, Virginia.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Orzechowski
authors.affiliation: Department of Obstetrics and Gynecology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Berghella
authors.affiliation: Department of Obstetrics and Gynecology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Baxter
mesh_terms: D000328:Adult; D054791:Cervical Length Measurement; D002585:Cesarean Section / Q000009:adverse effects; D005260:Female; D005865:Gestational Age; D006801:Humans; D016015:Logistic Models; D015999:Multivariate Analysis; D016017:Odds Ratio; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012372:ROC Curve; D012189:Retrospective Studies; D014219:Trial of Labor; D016064:Vaginal Birth after Cesarean / Q000706:statistics & numerical data*; D055815:Young Adult