title: Prediction of vaginal birth after cesarean delivery.
abstract: OBJECTIVE
  To examine factors associated with successful vaginal birth after cesarean (VBAC) and to validate a previously established prediction model.
  
  
  METHODS
  In a retrospective study, data were obtained for women with one prior low-transverse cesarean procedure who underwent a trial of labor with a cephalic singleton pregnancy at term at one UK hospital between January 2000 and August 2013. Univariate analysis and logistic regression analysis were used to identify maternal demographic characteristics significantly associated with successful VBAC and factors independently associated with this outcome, respectively. A prediction model was built, and predicted probabilities were compared with observed frequencies. For validation, probabilities were also calculated by a previous prediction model.
  
  
  RESULTS
  Overall, 1463 women formed the cohort. Successful vaginal delivery was achieved in 1050 (71.8%) women. The only factors significantly associated with unsuccessful VBAC were Asian (odds ratio [OR] 1.59, 95% confidence interval [CI] 1.14-2.23) or African (OR 1.80, 95% CI 1.23-2.64) ethnic origin, and previous cesarean for failure to progress (OR 6.39, 95% CI 4.81-8.49). The predicted and observed probability of successful VBAC were well correlated (Spearman ρ, 0.905; P=0.002). The established prediction model was less accurate.
  
  
  CONCLUSIONS
  Previous cesarean performed for failure to progress and Asian/African ethnic origin were associated with unsuccessful VBAC. The performance of a previous prediction model was inferior.
authors.affiliation: Department of Obstetrics and Gynecology, St George's University Hospital Foundation Trust, London, UK; St George's, University of London, London, UK. Electronic address: abhide@sgul.ac.uk.
authors.forename: Amarnath
authors.initials: A
authors.lastname: Bhide
authors.affiliation: Department of Obstetrics and Gynecology, St George's University Hospital Foundation Trust, London, UK.
authors.forename: Vedrana
authors.initials: V
authors.lastname: Caric
authors.affiliation: Department of Obstetrics and Gynecology, St George's University Hospital Foundation Trust, London, UK; St George's, University of London, London, UK.
authors.forename: Sabaratnam
authors.initials: S
authors.lastname: Arulkumaran
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D016015:Logistic Models; D008131:London; D008962:Models, Theoretical; D015999:Multivariate Analysis; D016017:Odds Ratio; D011247:Pregnancy; D012372:ROC Curve; D012189:Retrospective Studies; D014219:Trial of Labor; D016064:Vaginal Birth after Cesarean / Q000706:statistics & numerical data*
keywords: Cesarean; Delivery; Labor; Vaginal birth after cesarean