Is there a benefit to episiotomy at spontaneous vaginal delivery? A natural experiment

Objective: Our purpose was to examine the association between maternal vaginal and perineal morbidity and episiotomy performed at spontaneous vaginal delivery. Study Design: We obtained data from 17,483 consecutive spontaneous vaginal deliveries and compared the yearly rates of episiotomy, lacerations, and potential confounders with linear regression and stratified analyses. Results: Between 1976 and 1994 the use of episiotomy fell significantly (86.8% to 10.4%, R2=0.92, p=0.0001). This change was associated with a fall in the rate of third- and fourth-degree lacerations (9.0% to 4.2%, R2=0.59, p=0.0001) and a rise in the rate of intact perinea (10.3% to 26.5%, R2=0.68, p=0.0001) and vaginal lacerations (5.4% to 19.3%, R2=0.77, p=0.0001). These associations held in separate analyses stratified by parity and birth weight, except for the subgroup of nulliparous women with macrosomic infants. Conclusion: At our institution a large reduction in the use of episiotomy in spontaneous vaginal deliveries was associated with a significant reduction in perineal trauma in all groups of women except for nulliparous women with macrosomic infants.