title: The MFMU Cesarean Registry: factors affecting the success of trial of labor after previous cesarean delivery.
abstract: OBJECTIVE
  The purpose of this study was to determine which factors influence the likelihood of successful trial of labor (TOL) after 1 previous cesarean delivery (CD).
  
  
  METHODS
  We performed a multicenter 4-year prospective observational study (1999-2002) of all women with previous CD undergoing TOL. Women with term singleton pregnancies with 1 previous low transverse CD or unknown incision were included for analysis.
  
  
  RESULTS
  Fourteen thousand five hundred twenty-nine women underwent TOL, with 10,690 (73.6%) achieving successful VBAC. Women with previous vaginal birth had an 86.6% success rate compared with 60.9% in women without such a history (odds ratio [OR] 4.2; 95% CI 3.8-4.5; P < .001). TOL success rates were affected by previous indication for CD, need for induction or augmentation, cervical dilation on admission, birth weight, race, and maternal body mass index. Multivariate logistic regression analysis identified as predictive of TOL success: previous vaginal delivery (OR 3.9; 95% CI 3.6-4.3), previous indication not being dystocia (CPD/FTP) (OR 1.7; 95% CI 1.5-1.8), spontaneous labor (OR 1.6; 95% CI 1.5-1.8), birth weight <4000 g (OR 2.0; 95% CI 1.8-2.3), and Caucasian race (OR 1.8, 95% CI 1.6-1.9) (all P < .001). The overall TOL success rate in obese women (BMI > or = 30) was lower (68.4%) than in nonobese women (79.6%) (P < .001), and when combined with induction and lack of previous vaginal delivery, successful VBAC occurred in only 44.2% of cases.
  
  
  CONCLUSIONS
  Previous vaginal delivery including previous VBAC is the greatest predictor for successful TOL. Previous indication as dystocia, need for labor induction, or a maternal BMI > or = 30 significantly lowers success rates.
authors.affiliation: Department of Obstetrics and Gynecology at The Ohio State University College of Medicine and Public Health, Columbus, OH 43210-1228, USA. landon.l@osu.edu
authors.forename: Mark B
authors.initials: MB
authors.lastname: Landon
authors.forename: Sharon
authors.initials: S
authors.lastname: Leindecker
authors.forename: Catherine Y
authors.initials: CY
authors.lastname: Spong
authors.forename: John C
authors.initials: JC
authors.lastname: Hauth
authors.forename: Steven
authors.initials: S
authors.lastname: Bloom
authors.forename: Michael W
authors.initials: MW
authors.lastname: Varner
authors.forename: Atef H
authors.initials: AH
authors.lastname: Moawad
authors.forename: Steve N
authors.initials: SN
authors.lastname: Caritis
authors.forename: Margaret
authors.initials: M
authors.lastname: Harper
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Wapner
authors.forename: Yoram
authors.initials: Y
authors.lastname: Sorokin
authors.forename: Menachem
authors.initials: M
authors.lastname: Miodovnik
authors.forename: Marshall
authors.initials: M
authors.lastname: Carpenter
authors.forename: Alan M
authors.initials: AM
authors.lastname: Peaceman
authors.forename: Mary Jo
authors.initials: MJ
authors.lastname: O'Sullivan
authors.forename: Baha M
authors.initials: BM
authors.lastname: Sibai
authors.forename: Oded
authors.initials: O
authors.lastname: Langer
authors.forename: John M
authors.initials: JM
authors.lastname: Thorp
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ramin
authors.forename: Brian M
authors.initials: BM
authors.lastname: Mercer
authors.forename: Steven G
authors.initials: SG
authors.lastname: Gabbe
mesh_terms: D000328:Adult; D017604:Cesarean Section, Repeat / Q000706:statistics & numerical data*; D004420:Dystocia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007751:Labor, Induced / Q000706:statistics & numerical data; D016015:Logistic Models; D016017:Odds Ratio; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012307:Risk Factors; D014219:Trial of Labor; D016064:Vaginal Birth after Cesarean / Q000706:statistics & numerical data*