title: Intrapartum predictors of maternal levator ani injury.
abstract: BACKGROUND
  Damage to the pelvic floor during vaginal childbirth is common, and may take the form of levator avulsion or irreversible overdistension of the levator hiatus (microtrauma). Such trauma is a major risk factor for pelvic organ prolapse later in life. In this study we aimed to identify intrapartum risk factors for levator trauma.
  
  
  METHODS
  This is a retrospective analysis of data obtained in two perinatal studies on primiparous women. Between 2005 and 2014, 1148 women carrying an uncomplicated singleton pregnancy in the late third trimester were seen for 4D pelvic floor ultrasound and an interview. They were invited for a repeat assessment at three months postpartum.
  
  
  RESULTS
  Of 1148 women, 871 (76%) returned for assessment at a mean of five months postpartum. The datasets of 844 women were analyzed due to missing data or concurrent pregnancy in 27. In all, 452 (54%) had a normal vaginal delivery, 102 (12%) a vacuum, 55 (6%) a forceps, and 235 (28%) a cesarean section. On multivariate analysis forceps, length of second stage and obstetric anal sphincter tears were significantly associated with levator avulsion. There were no significant predictors identified for irreversible overdistension.
  
  
  CONCLUSIONS
  The use of forceps, a prolonged second stage, and obstetric anal sphincter tears were associated with levator avulsion. There were no associated intrapartum predictors for hiatal overdistension.
authors.affiliation: Sydney Medical School Nepean, University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia.
authors.forename: Jessica
authors.identifier: http://orcid.org/0000-0001-6554-4576
authors.initials: J
authors.lastname: Caudwell-Hall
authors.affiliation: Sydney Medical School Nepean, University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia.
authors.forename: Ixora
authors.identifier: http://orcid.org/0000-0001-8447-004X
authors.initials: I
authors.lastname: Kamisan Atan
authors.affiliation: NHMRC Clinical Trials Center, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Martin
authors.affiliation: Sydney Medical School Nepean, University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Guzman Rojas
authors.affiliation: Sydney Medical School Nepean, University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia.
authors.forename: Susanne
authors.identifier: http://orcid.org/0000-0002-3085-6489
authors.initials: S
authors.lastname: Langer
authors.affiliation: Sydney Medical School Nepean, University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia.|Liverpool Clinical School, University of Western Sydney, Sydney, New South Wales, Australia.
authors.forename: Kalai
authors.initials: K
authors.lastname: Shek
authors.affiliation: Sydney Medical School Nepean, University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia.
authors.forename: Hans P
authors.initials: HP
authors.lastname: Dietz
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000000981:diagnostic imaging / Q000293:injuries*; D036861:Delivery, Obstetric / Q000379:methods; D005260:Female; D006801:Humans; D022125:Lacerations / Q000453:epidemiology* / Q000517:prevention & control; D008427:Maternal Health Services; D009517:New South Wales / Q000453:epidemiology; D007744:Obstetric Labor Complications / Q000453:epidemiology* / Q000517:prevention & control; D009772:Obstetrical Forceps / Q000009:adverse effects; D017773:Pelvic Floor / Q000000981:diagnostic imaging / Q000293:injuries*; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D014463:Ultrasonography
keywords: Levator avulsion; birth trauma; forceps; pelvic organ prolapse; ultrasound; urogynecology