title: The levator ani muscle during pregnancy and major levator ani muscle defects diagnosed postpartum: a three- and four-dimensional transperineal ultrasound study.
abstract: OBJECTIVE
  To investigate associations between levator hiatus area and levator ani muscle function during pregnancy and major levator ani muscle defects postpartum.
  
  
  METHODS
  Observational prospective cohort study.
  
  
  METHODS
  University hospital, Norway.
  
  
  METHODS
  A cohort of 234 nulliparous women at 21 and 37 weeks of gestation, and at 6 weeks postpartum.
  
  
  METHODS
  Ultrasound measurements of the levator hiatus at rest, during pelvic floor muscle contraction, and during the Valsalva manoeuvre were taken at 21 and 37 weeks of gestation. Levator ani muscle function was estimated as the percentage changes in levator ani muscle length from rest to contraction, and the level of muscle stretch during the Valsalva manoeuvre. Major levator ani muscle defects were diagnosed at 6 weeks postpartum using tomographic ultrasound imaging.
  
  
  METHODS
  Associations between ultrasound measurements antepartum and major levator ani muscle defects postpartum.
  
  
  RESULTS
  Women with major levator ani muscle defects postpartum had significantly smaller levator hiatus area at rest and during the Valsalva manoeuvre at mid-pregnancy (mean difference 1.03 cm(2) , 95% CI 0.31-1.76; 2.92 cm(2) , 95% CI 1.77-4.07), and at 37 weeks of gestation (mean difference 1.47 cm(2) , 95% CI 0.62-2.32; 2.84 cm(2) , 95% CI 0.88-4.80), than women without such defects. They also had significantly less shortening of the levator ani muscle during contraction at 37 weeks of gestation.
  
  
  CONCLUSIONS
  Smaller levator hiatus area at rest and during the Valsalva manoeuvre at mid and late pregnancy, and less shortening of the levator ani muscle during contraction at 37 weeks of gestation, are associated with major levator ani muscle defects postpartum.
authors.affiliation: Faculty Division Akershus University Hospital, University of Oslo, Oslo, Norway.|Department of Obstetrics and Gynaecology, Akershus University Hospital, Lørenskog, Norway.
authors.forename: F
authors.initials: F
authors.lastname: Siafarikas
authors.affiliation: Department of Obstetrics and Gynaecology, Akershus University Hospital, Lørenskog, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Staer-Jensen
authors.affiliation: Department of Obstetrics and Gynaecology, Akershus University Hospital, Lørenskog, Norway.|Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors.forename: G
authors.initials: G
authors.lastname: Hilde
authors.affiliation: Department of Obstetrics and Gynaecology, Akershus University Hospital, Lørenskog, Norway.|Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Bø
authors.affiliation: Faculty Division Akershus University Hospital, University of Oslo, Oslo, Norway.|Department of Obstetrics and Gynaecology, Akershus University Hospital, Lørenskog, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Ellström Engh
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D009119:Muscle Contraction / Q000502:physiology*; D009664:Norway; D017773:Pelvic Floor / Q000000981:diagnostic imaging* / Q000503:physiopathology; D049590:Postpartum Period / Q000502:physiology; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000502:physiology; D011263:Pregnancy Trimester, Third / Q000502:physiology; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods; D014636:Valsalva Maneuver / Q000502:physiology; D055815:Young Adult
keywords: Levator hiatus; major levator ani muscle defects; pregnancy; transperineal ultrasound