title: [Does persistent occiput posterior position increase the risk of severe perineal laceration?].
abstract: OBJECTIVE
  To assess the risk of severe perineal lacerations (III and IV degrees) during vaginal deliveries in occiput posterior position.
  
  
  METHODS
  We conducted a retrospective cohort study of 9097 vaginal deliveries in a teaching hospital's maternity between January 1st 2005 and December 31st 2008. Risk factors associated with tears of the 3rd or 4th degree were studied by a multivariate logistic regression.
  
  
  RESULTS
  Severe perineal lacerations occurred in 1.69% of cases (n=152) and did not significantly vary between 2005 and 2008. Parity was a protective factor (OR 0.42; P<0.001; IC(95%) 0.29-0.60) whereas instrumental extraction was associated with an increased risk: vacuum (OR 3.95; P<0.001, IC(95%) 2.23-7.00) and forceps (OR 3.55; P<0.001, IC(95%) 2.33-5.42). macrosomia. Risks were also increased in fetal macrosomia and episiotomy did not protect the mother (respectively OR 1.41 P<0.001, IC(95%) 1.19-1.68 and OR 1.73; P<0.001, IC(95%) 1.16-2.57). Persistent occiput posterior position was not significantly associated with an anal sphincter injury (OR=1.70 P=0.059; IC(95%) 0.98-2.94).
  
  
  CONCLUSIONS
  In our series, occiput posterior position did not significantly impact the risk of severe perineal laceration. A manual rotation of the fetal head should be performed in case of associated risk factors.
authors.affiliation: Service de gynécologie-obstétrique, hôpital de la Croix-Rousse, hospices civils de Lyon, 103 Grande-Rue-de-la-Croix-Rousse, Lyon cedex 04, France. parasympathique@gmail.com
authors.forename: C
authors.initials: C
authors.lastname: Salameh
authors.forename: F
authors.initials: F
authors.lastname: Canoui-Poitrine
authors.forename: M
authors.initials: M
authors.lastname: Cortet
authors.forename: A
authors.initials: A
authors.lastname: Lafon
authors.forename: R-C
authors.initials: RC
authors.lastname: Rudigoz
authors.forename: C
authors.initials: C
authors.lastname: Huissoud
mesh_terms: D000328:Adult; D004841:Episiotomy; D005113:Extraction, Obstetrical; D005260:Female; D005320:Fetal Macrosomia / Q000150:complications; D006801:Humans; D007746:Labor Presentation; D022125:Lacerations / Q000209:etiology*; D010298:Parity; D010502:Perineum / Q000293:injuries*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000209:etiology; D012189:Retrospective Studies; D012306:Risk; D012720:Severity of Illness Index; D014710:Version, Fetal / Q000009:adverse effects / Q000379:methods*