title: The role of maternal age and episiotomy in the risk of anal sphincter tears during childbirth.
abstract: BACKGROUND
  Many women who experience anal sphincter tear will suffer from anal incontinence. The most important tool to avoid this is to recognise the obstetric risk factors involved and thereby prevent injury.
  
  
  OBJECTIVE
  The aim of this study was to analyse and evaluate the risk factors of anal sphincter tear during delivery.
  
  
  METHODS
  Of a total of 57,943 vaginal deliveries, we identified 565 women with partial or total rupture of the anal sphincter and compared these women with 565 controls without sphincter tear with respect to possible risk factors.
  
  
  RESULTS
  Several factors were significantly associated with sphincter tears, including nulliparity, birthweight, instrumental delivery, episiotomy, malpresentation, maternal age and epidural analgesia. The importance of these variables was further confirmed in a stepwise logistic regression analysis. Age was found to be a significant risk factor only when the birthweight was less than 4000 g. Episiotomy more than doubled the risk of sphincter tear when delivery was non-instrumental.
  
  
  CONCLUSIONS
  There are several independent risk factors that should be considered when making decisions regarding delivery mode. Maternal age and episiotomy in non-instrumental delivery are two of these.
authors.affiliation: Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden. eva.gerdin@akademiska.se
authors.forename: Eva
authors.initials: E
authors.lastname: Gerdin
authors.forename: Gudlaug
authors.initials: G
authors.lastname: Sverrisdottir
authors.forename: Amal
authors.initials: A
authors.lastname: Badi
authors.forename: Björn
authors.initials: B
authors.lastname: Carlsson
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Graf
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000293:injuries*; D036861:Delivery, Obstetric / Q000009:adverse effects*; D004841:Episiotomy; D005260:Female; D006801:Humans; D016015:Logistic Models; D008423:Maternal Age; D015999:Multivariate Analysis; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D012421:Rupture