title: Risk factors for severe obstetric perineal lacerations.
abstract: OBJECTIVE
  The aim of this study was to assess the occurrence of severe perineal lacerations in vaginal delivery and its relationship with predisposing clinical and obstetric factors.
  
  
  METHODS
  A retrospective cohort analysis using an electronic clinical database at a University Referral Center for high-risk pregnancies was performed. A total of 941 vaginal deliveries were analyzed, over 10 consecutive months in 2013 and 2014. The relationship between obstetric and clinical characteristics and lacerations, especially severe forms, was analyzed. The frequency and severity of birth canal lacerations were compiled and classified as mild (unintentional laceration grades I and II, and mediolateral episiotomy) and severe (grades III and IV). The crude and adjusted odds ratios and 95% confidence intervals were estimated in univariate and multivariate logistic regression models.
  
  
  RESULTS
  The overall incidence of perineal lacerations in vaginal delivery was 78.2% (n = 731). Lacerations were considered mild in 708 women (75.7%) and severe in 23 women (2.5%). Maternal age, parity, use of forceps, mediolateral episiotomy, and birth weight influenced the occurrence of some degree of tear. The chance of severe lacerations increased 1.77-fold per week with the gestational age (1.03-3.03, P = 0.025), while primiparity increased the chance of laceration 5.32-fold. Episiotomy did not show a protective effect against severe laceration occurrence (P = 0.999).
  
  
  CONCLUSIONS
  Severe perineal lacerations were associated with operative delivery, primiparity, gestational age, and epidural anesthesia. Episiotomy was not protective.
authors.affiliation: Department of Obstetrics and Gynaecology, Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190 - 2. andar, Belo Horizonte, 30130-100, Brazil. marilene.vale@gmail.com.
authors.forename: Marilene
authors.initials: M
authors.lastname: Vale de Castro Monteiro
authors.affiliation: Urogynaecology, City Council Para de Minas, Minas Gerais, Brazil.
authors.forename: Gláucia M Varella
authors.initials: GM
authors.lastname: Pereira
authors.affiliation: Department of Obstetrics and Gynaecology, Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190 - 2. andar, Belo Horizonte, 30130-100, Brazil.
authors.forename: Regina Amélia Pessoa
authors.initials: RA
authors.lastname: Aguiar
authors.affiliation: School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Rodrigo Leite
authors.initials: RL
authors.lastname: Azevedo
authors.affiliation: Department of Obstetrics and Gynaecology, Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190 - 2. andar, Belo Horizonte, 30130-100, Brazil.|Otto Cirne Maternity, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Mário Dias
authors.initials: MD
authors.lastname: Correia-Junior
authors.affiliation: Department of Obstetrics and Gynaecology, Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190 - 2. andar, Belo Horizonte, 30130-100, Brazil.|Center of Medical Informatics, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Zilma Silveira Nogueira
authors.initials: ZS
authors.lastname: Reis
mesh_terms: D000328:Adult; D015984:Causality; D015331:Cohort Studies; D036861:Delivery, Obstetric; D004841:Episiotomy; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D022125:Lacerations / Q000209:etiology*; D010502:Perineum / Q000293:injuries*; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Episiotomy; Obstetric labor complications; Perineal tears; Perineal trauma; Risk factors; Vaginal delivery