title: Racial/ethnic variations in perineal length and association with perineal lacerations: a prospective cohort study.
abstract: OBJECTIVE
  To examine the association between race/ethnicity, perineal length and the risk of perineal laceration.
  
  
  METHODS
  This is a prospective cohort study of a diverse group of women with singleton gestations in the third trimester of pregnancy. Perineal length was measured and mean values calculated for several racial/ethnic groups. Chi-squared analyses were used to examine rates of severe perineal laceration (third or fourth degree laceration) by race/ethnicity among women considered to have a short perineal length. Further, subgroup analyses were performed comparing nulliparas to multiparas.
  
  
  RESULTS
  Among 344 study participants, there was no statistically significant difference in mean perineal length by race/ethnicity (White 4.0 ± 1.1 cm, African-American 3.7 ± 1.0 cm, Latina 4.1 ± 1.1 cm, Asian 3.8 ± 1.0 cm, and other/unknown 4.0 ± 0.9 cm). Considering parity, more multiparous Asian and African-American women had a short perineal length (20.7 and 23.5%, respectively, p = 0.05). Finally, the rate of severe perineal lacerations in our cohort was 2.6% overall, but was 8.2% among Asian women (p = 0.04).
  
  
  CONCLUSIONS
  We did not find a relationship between short perineal length and risk of severe perineal laceration with vaginal delivery, or a difference in mean perineal length by maternal race/ethnicity. However, we did find that women of different racial/ethnic groups have varying rates of severe perineal laceration, with Asian women comprising the highest proportion.
authors.affiliation: Department of Obstetrics & Gynecology, Stanford Hospital & Clinics , Stanford, CA , USA .
authors.forename: Amanda
authors.initials: A
authors.lastname: Yeaton-Massey
authors.forename: Luchin
authors.initials: L
authors.lastname: Wong
authors.forename: Teresa N
authors.initials: TN
authors.lastname: Sparks
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Handler
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Meyer
authors.forename: Jesus M
authors.initials: JM
authors.lastname: Granados
authors.forename: Marina
authors.initials: M
authors.lastname: Stasenko
authors.forename: Anita
authors.initials: A
authors.lastname: Sit
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Caughey
mesh_terms: D000328:Adult; D036861:Delivery, Obstetric / Q000009:adverse effects*; D005006:Ethnicity; D005260:Female; D006801:Humans; D022125:Lacerations / Q000208:ethnology*; D007744:Obstetric Labor Complications / Q000208:ethnology*; D010298:Parity; D010502:Perineum / Q000293:injuries*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies
keywords: Perineal laceration; perineal length; race/ethnicity