title: Evaluating maternal recovery from labor and delivery: bone and levator ani injuries.
abstract: OBJECTIVE
  We sought to describe occurrence, recovery, and consequences of musculoskeletal (MSK) injuries in women at risk for childbirth-related pelvic floor injury at first vaginal birth.
  
  
  METHODS
  Evaluating Maternal Recovery from Labor and Delivery is a longitudinal cohort design study of women recruited early postbirth and followed over time. We report here on 68 women who had birth-related risk factors for levator ani (LA) muscle injury, including long second stage, anal tears, and/or older maternal age, and who were evaluated by MSK magnetic resonance imaging at both 7 weeks and 8 months' postpartum. We categorized magnitude of injury by extent of bone marrow edema, pubic bone fracture, LA muscle edema, and LA muscle tear. We also measured the force of LA muscle contraction, urethral pressure, pelvic organ prolapse, and incontinence.
  
  
  RESULTS
  In this higher-risk sample, 66% (39/59) had pubic bone marrow edema, 29% (17/59) had subcortical fracture, 90% (53/59) had LA muscle edema, and 41% (28/68) had low-grade or greater LA tear 7 weeks' postpartum. The magnitude of LA muscle tear did not substantially change by 8 months' postpartum (P = .86), but LA muscle edema and bone injuries showed total or near total resolution (P < .05). The magnitude of unresolved MSK injuries correlated with magnitude of reduced LA muscle force and posterior vaginal wall descent (P < .05) but not with urethral pressure, volume of demonstrable stress incontinence, or self-report of incontinence severity (P > .05).
  
  
  CONCLUSIONS
  Pubic bone edema and subcortical fracture and LA muscle injury are common when studied in women with certain risk factors. The bony abnormalities resolve, but levator tear does not, and is associated with levator weakness and posterior-vaginal wall descent.
authors.affiliation: School of Nursing, University of Michigan, Ann Arbor, MI; Department of Obstetrics and Gynecology, Medical School, University of Michigan, Ann Arbor, MI. Electronic address: janismm@umich.edu.
authors.forename: Janis M
authors.initials: JM
authors.lastname: Miller
authors.affiliation: School of Nursing, University of Michigan, Ann Arbor, MI; Department of Obstetrics and Gynecology, Medical School, University of Michigan, Ann Arbor, MI; Women's Studies Department, University of Michigan, Ann Arbor, MI.
authors.forename: Lisa Kane
authors.initials: LK
authors.lastname: Low
authors.affiliation: School of Nursing, University of Michigan, Ann Arbor, MI.
authors.forename: Ruth
authors.initials: R
authors.lastname: Zielinski
authors.affiliation: Arbor Research Collaborative for Health, Ann Arbor, MI.
authors.forename: Abigail R
authors.initials: AR
authors.lastname: Smith
authors.affiliation: Department of Obstetrics and Gynecology, Medical School, University of Michigan, Ann Arbor, MI.
authors.forename: John O L
authors.initials: JO
authors.lastname: DeLancey
authors.affiliation: Department of Radiology, Medical School, University of Michigan, Ann Arbor, MI.
authors.forename: Catherine
authors.initials: C
authors.lastname: Brandon
mesh_terms: D000328:Adult; D000367:Age Factors; D001003:Anal Canal / Q000293:injuries* / Q000473:pathology; D001853:Bone Marrow / Q000473:pathology; D015331:Cohort Studies; D003289:Convalescence; D036861:Delivery, Obstetric / Q000009:adverse effects*; D004487:Edema / Q000175:diagnosis; D005260:Female; D050723:Fractures, Bone / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D007748:Labor Stage, Second; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009135:Muscular Diseases / Q000175:diagnosis / Q000209:etiology; D007744:Obstetric Labor Complications / Q000175:diagnosis / Q000453:epidemiology*; D017773:Pelvic Floor / Q000293:injuries* / Q000473:pathology; D011247:Pregnancy; D011630:Pubic Bone / Q000293:injuries* / Q000473:pathology; D020127:Recovery of Function; D012307:Risk Factors; D055815:Young Adult
keywords: levator ani; magnetic resonance imaging; musculoskeletal injuries; pelvic floor; vaginal birth