Objective: The objective of the study was to evaluate the frequency of obstetrical anal sphincter injuries (OASIS) in women undergoing operative vaginal deliveries (OVD) and to assess whether a mediolateral episiotomy is protective for developing OASIS in these deliveries. Study Design: We performed a retrospective cohort study. Maternal and obstetrical characteristics of the 2861 women who delivered liveborn infants by an OVD at term in the years 2001-2009 were extracted from a clinical obstetrics database and were analyzed in a logistic regression model. Results: The frequency of OASIS was 5.7%. Women with a mediolateral episiotomy were at significantly lower risk for OASIS compared with the women without a mediolateral episiotomy in case of an OVD (adjusted odds ratio, 0.17; 95% confidence interval, 0.12-0.24). Conclusion: We found a 6-fold decreased odds for developing OASIS when a mediolateral episiotomy was performed in OVD. Therefore, we advocate the use of a mediolateral episiotomy in all operative vaginal deliveries to reduce the incidence of OASIS. © 2012 Mosby, Inc.
De Vogel, J., Van Der Leeuw-Van Beek, A., Gietelink, D., Vujkovic, M., De Leeuw, J. W., Van Bavel, J., & Papatsonis, D. (2012). The effect of a mediolateral episiotomy during operative vaginal delivery on the risk of developing obstetrical anal sphincter injuries. In American Journal of Obstetrics and Gynecology (Vol. 206, pp. 404.e1-404.e5). Mosby Inc. https://doi.org/10.1016/j.ajog.2012.02.008