title: Episiotomy - risk factors and outcomes.
abstract: OBJECTIVE
  To identify risk factors for mediolateral episiotomy, and evaluate the risk of obstetrical anal sphincter injury (OASI) among women with an episiotomy.
  
  
  METHODS
  A retrospective cohort study of all singletons vaginal deliveries at term between 2007 and 2014. Spontaneous and operative vaginal deliveries were compared separately, as well as nulliparous and multiparous women.
  
  
  RESULTS
  Overall, 41,347 women were included in the spontaneous vaginal delivery group: 12,585 (30.4%) nulliparous and 28,762 (69.6%) multiparous women. Risk factors for episiotomy (nulliparous) were maternal age (aOR 0.98), gestational age (GA, aOR 1.07), regional analgesia (RA, aOR 1.18), labor induction (aOR 1.17), meconium (aOR 1.37) and birth weight (BW, aOR 1.04). Episiotomy was associated with PPH (aOR 1.49). Among multiparous, risk factors were maternal age (aOR 1.04), previous vaginal delivery (aOR 0.38), GA (aOR 1.06), RA (aOR 1.22), meconium (aOR 1.22) and BW (aOR 1.05). Episiotomy was associated with 3rd degree perineal tear (aOR 2.26, 95% CI 1.03-4.97). Only birth weight (nulliparous) and previous vaginal deliveries (multiparous) were contributors for episiotomy in the OVD group.
  
  
  CONCLUSIONS
  Several risk factors for mediolateral episiotomy exist. Episiotomy does not protect nulliparous women, and may be associated with an increased risk for multiparous, for OASI. Therefore, the practice of routine episiotomy should be abandoned, and the practice of selective episiotomy reconsidered.
authors.affiliation: a Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Affiliated to the Sackler Faculty of Medicine, Tel-Aviv University , Ramat-Aviv , Israel.
authors.forename: Anat
authors.initials: A
authors.lastname: Shmueli
authors.affiliation: a Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Affiliated to the Sackler Faculty of Medicine, Tel-Aviv University , Ramat-Aviv , Israel.
authors.forename: Rinat
authors.initials: R
authors.lastname: Gabbay Benziv
authors.affiliation: b Lis Maternity Hospital, The Tel-Aviv Sourasky Medical Center, Tel Aviv, The Sackler Faculty of Medicine, Tel-Aviv University , Ramat-Aviv , Israel , and.
authors.forename: Liran
authors.initials: L
authors.lastname: Hiersch
authors.affiliation: b Lis Maternity Hospital, The Tel-Aviv Sourasky Medical Center, Tel Aviv, The Sackler Faculty of Medicine, Tel-Aviv University , Ramat-Aviv , Israel , and.
authors.forename: Eran
authors.initials: E
authors.lastname: Ashwal
authors.affiliation: c Department of Obstetrics and Gynecology , Meir Medical Center, Kfar Saba, The Sackler Faculty of Medicine, Tel-Aviv University , Ramat-Aviv , Israel.
authors.forename: Rami
authors.initials: R
authors.lastname: Aviram
authors.affiliation: b Lis Maternity Hospital, The Tel-Aviv Sourasky Medical Center, Tel Aviv, The Sackler Faculty of Medicine, Tel-Aviv University , Ramat-Aviv , Israel , and.
authors.forename: Yariv
authors.initials: Y
authors.lastname: Yogev
authors.affiliation: b Lis Maternity Hospital, The Tel-Aviv Sourasky Medical Center, Tel Aviv, The Sackler Faculty of Medicine, Tel-Aviv University , Ramat-Aviv , Israel , and.
authors.forename: Amir
authors.initials: A
authors.lastname: Aviram
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000293:injuries*; D004841:Episiotomy / Q000009:adverse effects* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D007744:Obstetric Labor Complications / Q000209:etiology*; D017063:Outcome Assessment, Health Care; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Mediolateral episiotomy; obstetrical anal sphincter injury; operative vaginal delivery; parity; spontaneous vaginal delivery