title: Prevalence and contributing factors of severe perineal damage following episiotomy-assisted vaginal delivery.
abstract: OBJECTIVE
  This study was conducted to investigate the risk factors of third- and fourth-degree lacerations following vaginal deliveries in Taiwanese women, and to offer clinical guidance for the reduction of severe perineal lacerations.
  
  
  METHODS
  A total of 1879 women who underwent vaginal deliveries assisted by midline episiotomy at a tertiary hospital were included. Obstetric risk factors were analyzed for women with and without third- and fourth-degree lacerations.
  
  
  RESULTS
  Two hundred and five deliveries (10.9%) resulted in third- or fourth-degree lacerations. Parity, duration of first and second stages of labor, rate of instrument-assisted vaginal deliveries, the newborn's birth weight and head circumference, and the ratio of the newborn's birth weight to maternal body mass index were significantly different between women with and without severe perineal lacerations. Logistic regression demonstrated that nulliparity (odds ratio = 3.626, p < 0.001), duration of second stage of labor (odds ratio = 1.102, p = 0.044), instrument-assisted vaginal delivery (odds ratio = 4.102, p < 0.001), and newborn's head circumference (odds ratio = 1.323, p < 0.001) were independent risk factors of severe perineal lacerations. Instrument-assisted vaginal delivery was a common independent risk factor for severe lacerations shared between primiparous and multiparous women.
  
  
  CONCLUSIONS
  With regard to severe perineal lacerations during vaginal delivery, there are multiple obstetric contributory factors despite routine episiotomy, among them, nulliparity, longer labor duration, greater newborn head circumference, and instrument-assisted vaginal delivery. The latter should only be performed after careful evaluation.
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.
authors.forename: Wu-Chiao
authors.initials: WC
authors.lastname: Hsieh
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan. Electronic address: ccjoliang@cgmh.org.tw.
authors.forename: Ching-Chung
authors.initials: CC
authors.lastname: Liang
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.
authors.forename: Dennis
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Shuenn-Dhy
authors.initials: SD
authors.lastname: Chang
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ho-Yen
authors.initials: HY
authors.lastname: Chueh
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: An-Shine
authors.initials: AS
authors.lastname: Chao
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D004841:Episiotomy / Q000009:adverse effects*; D005113:Extraction, Obstetrical / Q000009:adverse effects; D005260:Female; D006801:Humans; D022125:Lacerations / Q000453:epidemiology / Q000209:etiology*; D016015:Logistic Models; D007744:Obstetric Labor Complications / Q000453:epidemiology / Q000209:etiology*; D016017:Odds Ratio; D010502:Perineum / Q000293:injuries*; D011247:Pregnancy; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors
keywords: episiotomy; perineal laceration; vaginal delivery