title: Variation in hospital caesarean section rates and obstetric outcomes among nulliparae at term: a population-based cohort study.
abstract: OBJECTIVE
  To explore the variation in hospital caesarean section (CS) rates for nulliparous women, to determine whether different case-mix, labour and delivery, and hospital factors can explain this variation and to examine the association between hospital CS rates and outcomes.
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  New South Wales, 2009-2010.
  
  
  METHODS
  Nulliparous women with singleton cephalic live births at term.
  
  
  METHODS
  Random effect multilevel logistic regression models using linked hospital discharge and birth data.
  
  
  METHODS
  Prelabour and intrapartum CS rates following spontaneous labour or labour induction; maternal and neonatal severe morbidity rates.
  
  
  RESULTS
  Of 67 239 nulliparous women, 4902 (7.3%) had a prelabour CS, 39 049 (58.1%) laboured spontaneously, and 23 288 (34.6%) had labour induced. Overall, there were 18 875 (28.1%) CSs, with labour inductions twice as likely to result in an intrapartum CS compared with women with a spontaneous onset of labour (34.0% versus 15.5%). After adjusting for differences in case-mix, labour and delivery, and hospital factors, the overall variation in CS rates decreased by 78% for prelabour CSs, 52% for intrapartum CSs following spontaneous labour and 9% following labour induction. Adjusting for labour and delivery practices increased the unexplained variation in intrapartum CSs. The adjusted rates of severe maternal and neonatal morbidity were not significantly different across CS rate quintile groups, except for women in spontaneous labour, where the hospitals in the lowest CS quintile had the lowest neonatal morbidity rate.
  
  
  CONCLUSIONS
  Differences in clinical practice were substantial contributors to variation in intrapartum CS rates. Our findings suggest that CS rates in some hospitals could be lowered without adversely affect pregnancy outcomes.
authors.affiliation: Clinical and Population Perinatal Health Research, Kolling Institute, Northern Sydney Local Health District, St Leonards, NSW, Australia; Sydney Medical School Northern, University of Sydney, St Leonards, NSW, Australia; Department of Obstetrics and Gynaecology, Royal North Shore Hospital, Northern Sydney Local Health District, St Leonards, NSW, Australia.
authors.forename: T A
authors.initials: TA
authors.lastname: Nippita
authors.forename: Y Y
authors.initials: YY
authors.lastname: Lee
authors.forename: J A
authors.initials: JA
authors.lastname: Patterson
authors.forename: J B
authors.initials: JB
authors.lastname: Ford
authors.forename: J M
authors.initials: JM
authors.lastname: Morris
authors.forename: M C
authors.initials: MC
authors.lastname: Nicholl
authors.forename: C L
authors.initials: CL
authors.lastname: Roberts
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002585:Cesarean Section / Q000706:statistics & numerical data* / Q000639:trends; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007751:Labor, Induced / Q000706:statistics & numerical data*; D009517:New South Wales / Q000453:epidemiology; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome
keywords: Caesarean section; induction; labour; maternal outcome; neonatal outcome; spontaneous labour; term nullipara