title: Cervical dilation at time of caesarean delivery in nulliparous women: a population-based cohort study.
abstract: OBJECTIVE
  Our objective was to describe contemporary practice patterns in the timing of caesarean delivery in relation to cervical dilation, overall and by indication for caesarean. Our secondary objective was to examine how commonly caesarean delivery was performed for labour dystocia at dilations below 4 cm or without the use of oxytocin, overall and between hospitals.
  
  
  METHODS
  Retrospective, population-based cohort study.
  
  
  METHODS
  Ontario, Alberta, and British Columbia, Canada, 2008-2012.
  
  
  METHODS
  Nulliparous women in labour who delivered term singletons in cephalic position.
  
  
  METHODS
  Histograms were used to examine the distribution of cervical dilation at time of caesarean delivery, overall and by indication for caesarean. Funnel plots were used to illustrate variation in hospital-level rates of caesarean deliveries for labour dystocia that were performed early (<4 cm dilation) or without the use of oxytocin.
  
  
  METHODS
  Cervical dilation (in centimetres) at time of caesarean delivery.
  
  
  RESULTS
  The population-based cohort comprised 392 025 women, of whom 18.8% had a caesarean delivery. Of first-stage caesareans for labour dystocia in women who entered labour spontaneously, 13.6% (95% CI 12.9, 14.2) had dilations <4 cm [hospital-level inter-quartile range (IQR): 6.2% to 20.0%] and 29.5% (95% CI 28.6, 30.4) did not receive oxytocin to treat their dystocia (hospital-level IQR: 22.1-54.6%).
  
  
  CONCLUSIONS
  The proportion of caesareans done before 4 cm dilation or without oxytocin varies substantially across hospitals and suggests the need for institutions to review their practices and ensure that management of labour practice guidelines are followed.
  
  
  CONCLUSIONS
  Many caesareans for labour dystocia are performed early during labour (<4 cm dilation) or without oxytocin.
authors: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.
authors: C A
authors: CA
authors: Riddell
authors: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.
authors: J S
authors: JS
authors: Kaufman
authors: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.|Department of Economics, McGill University, Montreal, QC, Canada.
authors: E C
authors: EC
authors: Strumpf
authors: Department of Obstetrics and Gynecology, Jewish General Hospital, McGill University, Montreal, QC, Canada.|Centre for Clinical Epidemiology and Community Studies, Jewish General Hospital, Montreal, QC, Canada.
authors: H A
authors: HA
authors: Abenhaim
authors: Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, BC, Canada.
authors: J A
authors: JA
authors: Hutcheon
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D002584:Cervix Uteri / Q000502:physiology*; D002585:Cesarean Section / Q000706:statistics & numerical data*; D004106:Dilatation; D004420:Dystocia / Q000503:physiopathology*; D005260:Female; D019983:Guideline Adherence / Q000706:statistics & numerical data*; D006801:Humans; D007231:Infant, Newborn; D007745:Labor Onset / Q000502:physiology*; D010120:Oxytocics / Q000627:therapeutic use; D010298:Parity; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011247:Pregnancy; D012189:Retrospective Studies
chemical_list: D010120:Oxytocics
keywords: Caesarean delivery; cervical dilation; clinical guidelines; labour dystocia