title: The case for retaining severe perineal tears as an indicator of the quality of obstetric care.
abstract: BACKGROUND
  The incidence of severe perineal tears acquired during vaginal childbirth varies considerably across hospitals but its use as a safety and quality indicator is in jeopardy because of problems associated with accurate detection and recording.
  
  
  OBJECTIVE
  To understand and interpret time trends in the incidence of third- and fourth-degree perineal tears among women giving birth vaginally in 18 public maternity hospitals in South Australia, taking into account individualised risk factors for each birth.
  
  
  METHODS
  The risk-adjusted probability of a third- and fourth-degree tear was estimated for each of 65,598 singleton vaginal births (2002-2008), using a previously published regression model. The risk factors for each birth included maternal age; parity and ethnicity; assistance with instruments and episiotomy; shoulder dystocia; and infant birthweight. Plots of 'excess' tears were generated to help identify maternity services where the observed incidence of severe trauma differed from the expectation estimated from the risk profiles.
  
  
  RESULTS
  Three hospitals were identified at which there were systematically more tears than expected (given their risk profiles), and five hospitals were identified at which there were fewer tears. However, increased tearing at two hospitals coincided closely with improved advocacy for better detection and treatment of perineal tears (especially partial third-degree tears).
  
  
  CONCLUSIONS
  Statistical process control methods provide a powerful means of investigating temporal variations in the incidence of outcomes like severe perineal tears. Third- or fourth- degree tears should be retained as a quality indicator of maternity services, but it is likely that many third-degree tears currently go undetected.
authors.affiliation: Public Health Research Unit, Women's and Children's Hospital, Women's and Children's Health Network, Adelaide, South Australia, Australia. Peter.Baghurst@adelaide.edu.au
authors.forename: Peter A
authors.initials: PA
authors.lastname: Baghurst
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000293:injuries*; D005260:Female; D006771:Hospitals, Maternity / Q000592:standards* / Q000706:statistics & numerical data; D006779:Hospitals, Public / Q000592:standards* / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D022125:Lacerations / Q000453:epidemiology* / Q000209:etiology; D016015:Logistic Models; D007744:Obstetric Labor Complications / Q000453:epidemiology* / Q000209:etiology; D010043:Outcome and Process Assessment, Health Care; D010502:Perineum / Q000293:injuries*; D011247:Pregnancy; D019984:Quality Indicators, Health Care / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D020379:Risk Adjustment; D012307:Risk Factors; D013021:South Australia / Q000453:epidemiology; D015599:Trauma Severity Indices