Objective: After childbirth-related third- or fourth-degree perineal lacerations, the estimated incidence of wound disruption, fecal incontinence, or fistula ranges from 1% to 10%. Risk factors associated with severe laceration were analyzed at a single large teaching institution.

Study design: This study consisted of an analysis of data from the delivery database of Jackson Memorial Hospital, University of Miami, from 1989 through 1995. Included were vaginal deliveries for which complete information was available on maternal age, parity, ethnicity (white, black, or Hispanic), birth weight, episiotomy versus no episiotomy, type of episiotomy, and delivery (normal spontaneous, vacuum, or forceps). Multiple gestations, cases of shoulder dystocia, cesarean deliveries, patients with a history of cesarean delivery, and babies weighing <500 g at birth were excluded from this study. Both univariate and multivariate analyses were performed with variables such as maternal age, race, birth weight, type of episiotomy if any, and type of vaginal delivery.

Results: Among the 71,959 women who were delivered at our institution during the 7-year study period, 50,210 met the inclusion criteria. Through time there had been a decline in the use of episiotomy in general and of midline episiotomy in particular. The annual total number of deliveries also decreased. The episiotomy procedure per se and the type of episiotomy as well as birth weight, assisted vaginal delivery, and older maternal age were identified as independent risk factors associated with third- and fourth-degree perineal lacerations.

Conclusion: Although episiotomy is an important risk factor for severe lacerations after vaginal delivery, there are other significant independent risk factors, such as maternal age, birth weight, and assisted vaginal delivery, that should be considered in counseling and making decisions regarding delivery modality. Older patients who are being delivered of a first child are at higher risk for severe laceration. Midline episiotomy and assisted vaginal delivery should therefore be avoided in this population whenever possible, especially in the presence of a large baby.