Prior third- or fourth-degree perineal tears and recurrence risks

Objective: The objective of the present study is to determine the recurrenc e risk of a third-degree (into the anal sphincter) or a fourth-degree (into the rectum) perineal tear in women with a prior extensive laceration. Meth ods: Data were gathered from our computerized perinatal database between Ja nuary 1990 and December 1994. Women who had two consecutive singleton deliv eries were chosen as subjects. Results: The rate of an extensive perineal l aceration was greater if a tear had occurred in a previous pregnancy (19 of 178 cases, 10.7% vs. 56% of 1563 cases, 3.6%, odds ratio 3.4. A 95% confid ence interval: 1.8-6.4; p < 0.0001). A prior tear remained a risk factor af ter controlling for other variables (epidural analgesia, episiotomy, oxytoc in use, operative vaginal delivery, fetal macrosomia). Conclusion: A prior third-degree or fourth-degree perineal tear is associated with a 3.4-fold i ncreased risk of a recurrent severe obstetrical laceration. (C) 1999 Intern ational Federation of Gynecology and Obstetrics.