title: Analysis of caesarean section rates over time in a single Swiss centre using a ten-group classification system.
abstract: OBJECTIVE
  Caesarean section (CS) rates have risen over the past two decades. The aim of this observational study was to identify time-dependent variations in CS and vaginal delivery rates over a period of 11 years.
  
  
  METHODS
  All deliveries (13,701 deliveries during the period 1999-2009) at the University Women's Hospital Bern were analysed using an internationally standardised and approved ten-group classification system. Caesarean sections on maternal request (CSMR) were evaluated separately.
  
  
  RESULTS
  We detected an overall CS rate of 36.63% and an increase in the CS rate over time (p <0.001). Low-risk profile groups were the two largest populations and displayed low CS rates, with significantly decreasing relative size over time. The relative size of groups with induced labour increased significantly, but this did not have an impact on the overall CS rate. Pregnancies complicated by breech position, multiple pregnancies and abnormal lies did not have an impact on overall CS rate. The biggest contributor to a high CS rate was preterm delivery and the existence of a uterine scar from a previous CS. CSMR was 1.45% and did not have an impact on the overall CS rate.
  
  
  CONCLUSIONS
  The observational study identified wide variations in caesarean section and vaginal delivery rates across the groups over time, and a shift towards high-risk populations was noted. The biggest contributors to high CS rates were identified; namely, previous uterine scar and preterm delivery. Interventions aiming to reduce CS rates are planned.
authors.affiliation: Inselspital, Bern University Hospital, SWITZERLAND; martin.mueller@insel.ch.
authors.forename: Martin
authors.initials: M
authors.lastname: Mueller
authors.forename: Laura
authors.initials: L
authors.lastname: Kolly
authors.forename: Marc
authors.initials: M
authors.lastname: Bauman
authors.forename: Sara
authors.initials: S
authors.lastname: Imboden
authors.forename: Daniel
authors.initials: D
authors.lastname: Surbek
mesh_terms: D000328:Adult; D001946:Breech Presentation / Q000601:surgery; D002585:Cesarean Section / Q000009:adverse effects / Q000639:trends*; D002921:Cicatrix / Q000209:etiology / Q000601:surgery; D000013:Congenital Abnormalities / Q000601:surgery; D005260:Female; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D007751:Labor, Induced / Q000639:trends; D010298:Parity; D057240:Patient Preference / Q000706:statistics & numerical data; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data; D047928:Premature Birth / Q000601:surgery; D018570:Risk Assessment; D013557:Switzerland