title: Perineal body length and lacerations at delivery.
abstract: OBJECTIVE
  To define normal perineal body length during labor and determine if a shortened perineal body is associated with perineal lacerations or operative vaginal delivery.
  
  
  METHODS
  We reviewed charts of patients admitted for labor over a 4-month period. The perineal body was measured by the admitting physician and delivery outcomes obtained from inpatient records. Patients were excluded for malpresentation, multiple gestation, gestational age < 36 weeks, incomplete records and scheduled cesarean delivery. To determine if differences existed between patients with perineal body measurements available and those without, chi2 analysis was used, with P<.05 considered significant. Multiple logistic regression was used to control for confounding variables and determine if a shortened perineal body affected the incidence of operative vaginal delivery and significant lacerations at vaginal delivery.
  
  
  RESULTS
  A total of 234 patients met our inclusion criteria; perineal body measurements were available for 133 (57%). The average perineal body length was 3.90 cm (+/-0.70). Patients with a perineal body of < or = 2.5 cm had a significantly higher chance of sustaining a third- or fourth-degree laceration (40% vs. 5.6%, P=.004). This risk remained after controlling for both operative vaginal delivery and episiotomy. The incidence of operative vaginal delivery was greater (28.5% vs. 9.2%, P =.006) for patients with a perineal body < or = 3.5 cm.
  
  
  CONCLUSIONS
  There is an increased risk of significant lacerations and operative vaginal delivery in patients with a shortened perineal body.
authors.affiliation: Department of Obstetrics and Gynecology, National Naval Medical Center, Bethesda, Maryland, USA. deering95@hotmail.com
authors.forename: Shad H
authors.initials: SH
authors.lastname: Deering
authors.forename: Nicole
authors.initials: N
authors.lastname: Carlson
authors.forename: Michael
authors.initials: M
authors.lastname: Stitely
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Allaire
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Satin
mesh_terms: D000328:Adult; D000886:Anthropometry; D036861:Delivery, Obstetric / Q000009:adverse effects*; D005260:Female; D006801:Humans; D022125:Lacerations / Q000209:etiology*; D010502:Perineum / Q000033:anatomy & histology* / Q000293:injuries*; D011247:Pregnancy; D012016:Reference Values; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors