Objective: We assessed whether women who had a perineal trauma (episiotomy or spontaneous tear of the second degree or higher) at the first delivery were at increased risk for spontaneous perineal tears at the next delivery, and whether the risk increases with the severity of previous perineal trauma.
Design: Retrospective cohort study.
Population: We included data from 1895 women who had their first and second deliveries at Saint-Sacrement Hospital, Quebec City, Canada, between 1985 and 1994. Our study was restricted to women who gave birth vaginally to a single living neonate at their first 2 deliveries and who did not have an episiotomy at the second delivery. We extracted the data from the Department of Obstetrics computerized database.
Outcomes measured: Spontaneous perineal tears (of second degree or higher) at the second delivery.
Results: Having a perineal trauma at the first delivery more than tripled the risk (relative risk=3.3; 95% confidence interval, 2.6-4.2) of spontaneous perineal tears at the second delivery. The risk of spontaneous perineal tears at the second delivery increased with the severity of previous perineal trauma at birth.
Conclusions: Our results show that the risk of spontaneous perineal tears at subsequent deliveries increases with the presence and the severity of perineal trauma at the first delivery.