title: Maternal Asian ethnicity and the risk of anal sphincter injury.
abstract: OBJECTIVE
  To examine associations between maternal Asian ethnicity (South Asian and South East/East Asian) and anal sphincter injury.
  
  
  METHODS
  Retrospective cross-sectional study, comparing outcomes for Asian women with those of Australian and New Zealand women.
  
  
  METHODS
  A large metropolitan maternity service in Victoria, Australia.
  
  
  METHODS
  Australian/New Zealand, South Asian and South East/East Asian women who had a singleton vaginal birth from 2006 to 2012.
  
  
  METHODS
  The relation between maternal ethnicity and anal sphincter injury was assessed by logistic regression, adjusting for potential confounders.
  
  
  METHODS
  Anal sphincter injury was defined as a third or fourth degree tear (with or without episiotomy).
  
  
  RESULTS
  Among 32,653 vaginal births there was a significant difference in the rate of anal sphincter injury by maternal region of birth (p < 0.001). After adjustment for confounders, nulliparous women born in South Asian and South East/East Asia were 2.6 (95% confidence interval 2.2-3.3; p < 0.001) and 2.1 (95% confidence interval 1.7-2.5; p < 0.001) times more likely to sustain an anal sphincter injury than Australian/New Zealand women, respectively. Parous women born in South Asian and South East/East Asia were 2.4 (95% confidence interval 1.8-3.2; p < 0.001) and 2.0 (95% confidence interval 1.5-2.7; p < 0.001) times more likely to sustain an anal sphincter injury than Australian/New Zealand women, respectively.
  
  
  CONCLUSIONS
  There are ethnic differences in the rates of anal sphincter injury not fully explained by known risk factors for such trauma. This may have implications for care provision.
authors.affiliation: The Ritchie Centre, MIMR-PHI Institute, Monash University, Clayton, Victoria, Australia; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia.
authors.forename: Miranda
authors.initials: M
authors.lastname: Davies-Tuck
authors.forename: Mary-Anne
authors.initials: MA
authors.lastname: Biro
authors.forename: Joanne
authors.initials: J
authors.lastname: Mockler
authors.forename: Lynne
authors.initials: L
authors.lastname: Stewart
authors.forename: Euan M
authors.initials: EM
authors.lastname: Wallace
authors.forename: Christine
authors.initials: C
authors.lastname: East
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000293:injuries*; D001208:Asia / Q000208:ethnology; D003430:Cross-Sectional Studies; D036861:Delivery, Obstetric / Q000009:adverse effects* / Q000706:statistics & numerical data; D004841:Episiotomy / Q000706:statistics & numerical data; D005113:Extraction, Obstetrical / Q000009:adverse effects; D005260:Female; D006801:Humans; D022125:Lacerations / Q000208:ethnology*; D016015:Logistic Models; D008875:Middle Aged; D009520:New Zealand / Q000208:ethnology; D007744:Obstetric Labor Complications / Q000208:ethnology*; D018743:Perinatal Care / Q000706:statistics & numerical data; D011247:Pregnancy; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D014739:Victoria / Q000453:epidemiology; D016387:Women's Health / Q000208:ethnology*; D055815:Young Adult
keywords: Maternal ethnicity; anal sphincter injury; episiotomy; perineum; risk factors