title: Episiotomy increases perineal laceration length in primiparous women.
abstract: OBJECTIVE
  The aim of this study was to determine the clinical factors that contribute to posterior perineal laceration length.
  
  
  METHODS
  A prospective observational study was performed in 80 consenting, mostly primiparous women with term pregnancies. Posterior perineal lacerations were measured immediately after delivery. Numerous maternal, fetal, and operator variables were evaluated against laceration length and degree of tear. Univariate and multivariate regression analyses were performed to evaluate laceration length and parametric clinical variables. Nonparametric clinical variables were evaluated against laceration length by the Mann-Whitney U test.
  
  
  RESULTS
  A multivariate stepwise linear regression equation revealed that episiotomy adds nearly 3 cm to perineal lacerations. Tear length was highly associated with the degree of tear (R = 0.86, R(2) = 0.73) and the risk of recognized anal sphincter disruption. None of 35 patients without an episiotomy had a recognized anal sphincter disruption, but 6 of 27 patients with an episiotomy did (P <.001). Body mass index was the only maternal or fetal variable that showed even a slight correlation with laceration length (R = 0.30, P =.04).
  
  
  CONCLUSIONS
  Episiotomy is the overriding determinant of perineal laceration length and recognized anal sphincter disruption.
authors.affiliation: Department of Reproductive Medicine, The University of California, San Diego Medical Center, 92103-8433, USA.
authors.forename: C W
authors.initials: CW
authors.lastname: Nager
authors.forename: J P
authors.initials: JP
authors.lastname: Helliwell
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000503:physiopathology; D001004:Anus Diseases / Q000209:etiology / Q000503:physiopathology; D015992:Body Mass Index; D004841:Episiotomy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D022125:Lacerations / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D016014:Linear Models; D010502:Perineum / Q000293:injuries*; D011247:Pregnancy; D011446:Prospective Studies