title: Occurrence and clinical predictors of operative delivery for the vertex second twin after normal vaginal delivery of the first twin.
abstract: OBJECTIVE
  This study was undertaken to estimate occurrence and explore clinical predictors of abdominal and vaginal operative delivery in vertex second twin after normal vaginal delivery of the first twin.
  
  
  METHODS
  Data from a historical cohort study that was based on a twin registry in the United States (1995-1997) were used.
  
  
  RESULTS
  Among 42,417 vertex second twins following normal vaginal delivery of the first twins, rates of abdominal and vaginal operative delivery were 6.3% and 8.3%, respectively. Cord prolapse, fetal distress, maternal complications, abnormal labor, and birth weight 25% larger than first twin were the most important predicators for operative deliveries. Fetal distress and cord prolapse had a stronger effect on abdominal than vaginal operative delivery.
  
  
  CONCLUSIONS
  In general population, abdominal and vaginal operative delivery rates were 6.3% and 8.3%, respectively, in vertex second twin after normal vaginal delivery of the first twin. The most important predictors for operative delivery are cord prolapse and fetal distress.
authors.affiliation: OMNI Research Group, Division of Maternal-Fetal Medicine, University of Ottawa, Faculty of Medicine, Canada.
authors.forename: Qiuying
authors.initials: Q
authors.lastname: Yang
authors.forename: Shi Wu
authors.initials: SW
authors.lastname: Wen
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
authors.forename: Karen
authors.initials: K
authors.lastname: Fung Kee Fung
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
mesh_terms: D000328:Adult; D001722:Birth Order; D002585:Cesarean Section / Q000706:statistics & numerical data*; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D005316:Fetal Distress / Q000453:epidemiology* / Q000209:etiology / Q000601:surgery*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007746:Labor Presentation; D008297:Male; D007744:Obstetric Labor Complications / Q000453:epidemiology / Q000209:etiology / Q000601:surgery; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome; D014427:Twins; D014481:United States / Q000453:epidemiology