title: The relationship between cervical dilatation at initial presentation in labour and subsequent intervention.
abstract: OBJECTIVE
  To examine the relationship between the cervical dilatation at which women present in labour and the subsequent likelihood of caesarean section.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  University teaching hospital.
  
  
  METHODS
  3,220 women met the entry criteria from 14,050 deliveries between January 1995 and December 1999.
  
  
  METHODS
  Women meeting the following criteria were identified: those in spontaneous labour with a singleton pregnancy and a cephalic presentation at 37-42 weeks of gestation; all women delivering within 36 hours of first presentation were included. Women who had spontaneous rupture of the membranes before first attendance were excluded.
  
  
  METHODS
  The primary outcome was the rate of caesarean section. Secondary outcomes were operative vaginal delivery, fetal weight, cord pH, five minute Apgar score, length of labour, labour augmentation with oxytocin and epidural analgesia.
  
  
  RESULTS
  The risk of caesarean section decreased with increasing cervical dilatation at presentation. This was true for nulliparous (n = 1,168) and parous women (n = 2,052). The caesarean section rate of nulliparous women presenting at 0-3cm (n = 812) was 10.3%, compared with 4.2% for those presenting at 4cm-10 cm (n = 356), and the mean duration of labour before presentation was 2.0 hours versus 4.5 hours, respectively (P = 0.0001). For parous women the caesarean section rates were 5.7% and 1.3%, respectively (P = 0.0001). There were significantly greater frequencies of use of oxytocin and epidural analgesia by women presenting earlier in labour. The caesarean section rate of 185 nulliparae (15.8%) who were initially allowed home was no different from those admitted immediately (9.2% vs 8.2%, P = 0.67). Similarly, 196 (9.5%) of multiparae went home and had a caesarean section rate of 3.6%, compared with 3.1% if admitted immediately (P = 0.76).
  
  
  CONCLUSIONS
  Women who present to hospital at 0-3cm spend less time in labour before presentation and are more likely to have obstetric intervention than those presenting in more advanced labour. Outcomes were similar whether or not the woman was initially allowed home.
authors.affiliation: Division of Maternal-Fetal Medicine, Ottawa Hospital, University of Ottawa, ON, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Holmes
authors.forename: L W
authors.initials: LW
authors.lastname: Oppenheimer
authors.forename: S W
authors.initials: SW
authors.lastname: Wen
mesh_terms: D000328:Adult; D001034:Apgar Score; D001724:Birth Weight; D002585:Cesarean Section / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007747:Labor Stage, First / Q000502:physiology*; D008423:Maternal Age; D007744:Obstetric Labor Complications / Q000209:etiology / Q000601:surgery; D010298:Parity; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D012307:Risk Factors