title: Anal sphincter tears at spontaneous delivery: a comparison of five hospitals in Norway.
abstract: OBJECTIVE
  To analyze circumstances relating to severe anal sphincter tears occurring at spontaneous delivery, in view of reported differences in practice regarding manual perineal protection during delivery.
  
  
  METHODS
  Cohort study of midwife-conducted non-operative vaginal deliveries.
  
  
  METHODS
  Five Norwegian hospitals with 12,438 consecutive deliveries during a 12-month period.
  
  
  METHODS
  Data from 357 women sustaining third and fourth grade anal sphincter tears (2.9%) were analyzed.
  
  
  METHODS
  Different incidence of major perineal tears.
  
  
  RESULTS
  Sphincter tear incidence varied significantly between the five hospitals, from 1.3 to 4.7% (p<0.001, RR=3.14 (CI: 2.38-5.56)). There was no significant difference between the five hospitals when other risk variables were compared. Use of oxytocin in the second phase of labor and of epidural analgesia was significantly more often applied in the hospital with the lowest rate of sphincter tears. The midwives' perception of having applied perineal support was not significantly different between the two hospitals with the highest and the lowest incidence of sphincter tear.
  
  
  CONCLUSIONS
  The observed difference in incidence of sphincter tear between the hospitals remains unexplained, but could be due to different perineal protection handling techniques.
authors.affiliation: Asker and Baerum Hospital, Oslo, Norway. annelill.valbo@sabhf.no
authors.forename: Annelill
authors.initials: A
authors.lastname: Valbø
authors.forename: Leif
authors.initials: L
authors.lastname: Gjessing
authors.forename: Christine
authors.initials: C
authors.lastname: Herzog
authors.forename: Jeanne Mette
authors.initials: JM
authors.lastname: Goderstad
authors.forename: Katariina
authors.initials: K
authors.lastname: Laine
authors.forename: Anne Marte
authors.initials: AM
authors.lastname: Valset
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000293:injuries*; D015360:Analgesia, Epidural / Q000379:methods; D001724:Birth Weight; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000009:adverse effects* / Q000379:methods*; D004841:Episiotomy / Q000379:methods; D005260:Female; D005865:Gestational Age; D006801:Humans; D007746:Labor Presentation; D008880:Midwifery / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data*; D009664:Norway; D007744:Obstetric Labor Complications; D010121:Oxytocin / Q000008:administration & dosage; D010502:Perineum / Q000293:injuries; D011247:Pregnancy; D012307:Risk Factors; D015599:Trauma Severity Indices
chemical_list: D010121:Oxytocin