title: Severe perineal laceration during operative vaginal delivery: the impact of occiput posterior position.
abstract: OBJECTIVE
  To identify risk factors for severe (third/fourth degree) perineal laceration with operative vaginal delivery (OVD, forceps or vacuum).
  
  
  METHODS
  Case-control study comparing singleton OVDs with or without severe laceration (n=138).
  
  
  RESULTS
  In multivariable analyses, severe perineal laceration was associated with occiput posterior (OP) position at delivery, vaginal nulliparity, use of forceps, longer period pushing in the second stage and lower gestational age, but not birth weight, labor induction or episiotomy. Among 29 OP patients at full dilation, 9/13 (69%) attempted rotations to occiput anterior (OA) were successful, and 14/16 (88%) patients in whom rotation was not attempted remained OP at delivery. Successful rotation from OP to OA was associated with fewer severe lacerations than no attempt or unsuccessful rotation (22 vs 75%, P=0.01).
  
  
  CONCLUSIONS
  Severe perineal laceration during OVD is associated with OP position at delivery and is reduced threefold in patients successfully rotated from OP to OA.
authors.affiliation: 1] Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL, USA [2] Department of Obstetrics and Gynecology, The University of Chicago, Chicago, IL, USA.
authors.forename: E
authors.initials: E
authors.lastname: Hirsch
authors.affiliation: Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL, USA.
authors.forename: R
authors.initials: R
authors.lastname: Elue
authors.affiliation: 1] Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL, USA [2] Department of Obstetrics and Gynecology, The University of Chicago, Chicago, IL, USA.
authors.forename: A
authors.initials: A
authors.lastname: Wagner
authors.affiliation: 1] Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL, USA [2] Department of Obstetrics and Gynecology, The University of Chicago, Chicago, IL, USA.
authors.forename: K
authors.initials: K
authors.lastname: Nelson
authors.affiliation: 1] Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL, USA [2] Department of Obstetrics and Gynecology, The University of Chicago, Chicago, IL, USA.
authors.forename: R K
authors.initials: RK
authors.lastname: Silver
authors.affiliation: 1] Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL, USA [2] Department of Obstetrics and Gynecology, The University of Chicago, Chicago, IL, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Obstetrics and Gynecology, NorthShore University HealthSystem, Evanston, IL, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Adams
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005113:Extraction, Obstetrical / Q000009:adverse effects* / Q000295:instrumentation; D005260:Female; D005333:Fetus / Q000503:physiopathology; D006801:Humans; D022125:Lacerations; D015999:Multivariate Analysis; D007744:Obstetric Labor Complications / Q000209:etiology*; D009772:Obstetrical Forceps; D010502:Perineum / Q000293:injuries*; D011247:Pregnancy; D012307:Risk Factors; D014620:Vacuum Extraction, Obstetrical / Q000009:adverse effects