title: Identification of women at high risk for severe perineal lacerations.
abstract: OBJECTIVE
  To evaluate the frequency and to identify the risk factors of severe perineal lacerations and the subgroup of women exposed to the highest risk for these complications.
  
  
  METHODS
  We conducted a case-control study in a large cohort of women for which vaginal delivery management consisted in systematic perineal support and restrictive use of mediolateral episiotomy. The case group comprised women with severe perineal lacerations while the control group comprised women without severe perineal lacerations. Maternal, labor, delivery and neonatal characteristics were analyzed in logistic regression models and a classification and regression tree (CART) was constructed.
  
  
  RESULTS
  Between 2000 and 2009, 19,442 women delivered vaginally in our centre, 88 of whom had severe perineal lacerations (0.5%). Instrumental delivery (aOR 4.17, 95% CI 2.51-6.90), nulliparity (aOR 2.58, 95% CI 1.55-4.29), persistent posterior orientation (aOR 2.24, 95% CI 1.02-4.94) and increased birth weight (aOR 1.28, 95% CI 1.03-1.60) were independent risk factors of severe perineal lacerations whereas mediolateral episiotomy had a protective effect (aOR 0.38, 95% CI 0.23-0.63). CART identified instrumental delivery of neonates smaller than 4500 g in persistent posterior orientation in nullipara without mediolateral episiotomy as the clinical situation associated with the highest risk of severe perineal lacerations (12.5%). Conversely, patients with the lowest risk (0.1%) were those delivering spontaneously, neonates larger than 3200 g after mediolateral episiotomy.
  
  
  CONCLUSIONS
  Instrumental delivery, nulliparity, persistent posterior orientation and increased birth weight are independently associated with severe perineal lacerations. Restrictive use of mediolateral episiotomy protects against severe perineal lacerations especially in case of instrumental delivery.
authors.affiliation: AP-HP, Hôpital Robert Debré, Service de Gynécologie Obstétrique, 75019 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France. Electronic address: thomas.schmitz@rdb.aphp.fr.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz
authors.affiliation: Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France; AP-HP, Hôpital Robert Debré, Unité d'Epidémiologie Clinique, 75019 Paris, France; Inserm, CIE 5, 75019 Paris, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Alberti
authors.affiliation: AP-HP, Hôpital Robert Debré, Unité d'Epidémiologie Clinique, 75019 Paris, France; Inserm, CIE 5, 75019 Paris, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Andriss
authors.affiliation: AP-HP, Hôpital Robert Debré, Service de Gynécologie Obstétrique, 75019 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France.
authors.forename: Constance
authors.initials: C
authors.lastname: Moutafoff
authors.affiliation: AP-HP, Hôpital Robert Debré, Service de Gynécologie Obstétrique, 75019 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Oury
authors.affiliation: AP-HP, Hôpital Robert Debré, Service de Gynécologie Obstétrique, 75019 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Sibony
mesh_terms: D000328:Adult; D001724:Birth Weight; D016022:Case-Control Studies; D004841:Episiotomy; D005113:Extraction, Obstetrical / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007746:Labor Presentation; D022125:Lacerations / Q000453:epidemiology* / Q000209:etiology*; D007744:Obstetric Labor Complications / Q000209:etiology; D010298:Parity; D010502:Perineum / Q000293:injuries*; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: Episiotomy; Instrumental delivery; Perineal laceration