ASSOCIATION BETWEEN MEDIAN EPISIOTOMY AND SEVERE PERINEAL LACERATIONSIN PRIMIPAROUS WOMEN

Objective: To evaluate the association between median episiotomy and s evere (third- and fourth-degree) perineal lacerations in primiparous w omen. Design: Retrospective cohort study. Setting: University-affiliat e hospital providing secondary obstetric care in Quebec City. Patients : A total of 6522 primiparous women who gave birth vaginally to a sing le live baby in cephalic position between 1985 and 1993. Outcome measu re: Incidence of third- and fourth-degree perineal lacerations. Result s: Median episiotomy was performed in 4390 women (67.3%). A total of 1 002 women (15.4%) had a third- or fourth-degree laceration. The freque ncy of severe perineal lacerations was 20.6% with episiotomy and 4.5% without episiotomy (relative risk [RR] 4.58, 95% confidence interval [ CI] 3.74-5.62). This association persisted after adjustment by stratif ied analysis for type of delivery and birth weight (RR 3.03, 95% CI 2. 52-3.63) and by logistic regression for type of delivery, birth weight , epidural analgesia, shoulder dystocia, baby's head circumference, ex perience of the physician and year of delivery (odds ratio 3.58, 95% C l 2.84-4.50). Conclusion: Median episiotomy is strongly associated wit h third- and fourth-degree perineal lacerations in primiparous women. Reducing the use of this procedure could decrease the occurrence of se vere perineal tears.