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

OBJECTIVE: The objective of the present study is to determine the recurrence 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. METHODS: Data were gathered from our computerized perinatal database between January 1990 and December 1994. Women who had two consecutive singleton deliveries were chosen as subjects. RESULTS: The rate of an extensive perineal laceration 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% confidence interval: 1.8-6.4; p < 0.0001). A prior tear remained a risk factor after controlling for other variables (epidural analgesia, episiotomy, oxytocin use, operative vaginal delivery, fetal macrosomia). CONCLUSION: A prior third-degree or fourth-degree perineal tear is associated with a 3.4-fold increased risk of a recurrent severe obstetrical laceration.