title: Obstetric parameters affecting success in a trial of labor: designation of a scoring system.
abstract: OBJECTIVE
  We sought to characterize risk factors in patients undergoing trial of labor after previous cesarean section and to determine whether a subset of patients at high risk of having an unsuccessful trial of labor consequently suffer greater morbidity.
  
  
  METHODS
  A 13-month chart review analyzed 264 labors with documented transverse lower uterine segment scars. Historic and physical examination variables were recorded, and a scoring system was constructed to evaluate successful vaginal delivery after cesarean.
  
  
  RESULTS
  Successful vaginal delivery occurred in 192 patients, resulting in a rate of vaginal birth after cesarean of 72.7%. Four variables significantly lower the rate of vaginal birth after cesarean. Of patients scoring 0 (no variables present), 91.5% were successfully delivered vaginally. Scores of 1, 2, and 3 to 4 were associated with the success of vaginal birth after cesarean in 73.9%, 66.7%, and 46.1% of patients, respectively. A score of 3 to 4 did not increase maternal or fetal morbidity in trial-of-labor patients.
  
  
  CONCLUSIONS
  We constructed a scoring system to evaluate the success of vaginal birth after cesarean. Trial of labor in the subset of patients with the lowest success rate does not increase morbidity.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, University of Texas Health Science Center, Houston.
authors.forename: L R
authors.initials: LR
authors.lastname: Troyer
authors.forename: V M
authors.initials: VM
authors.lastname: Parisi
mesh_terms: D002585:Cesarean Section; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D008428:Maternal Mortality; D008499:Medical Records; D011183:Postoperative Complications; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D012307:Risk Factors; D014219:Trial of Labor