Does the implementation of a restrictive episiotomy policy for operative deliveries increase the risk of obstetric anal sphincter injury?

Abstract

Purpose: Our main objective was to investigate whether the implementation of a restrictive episiotomy policy in operative deliveries changes the incidence of obstetric anal sphincter injury (OASI).

Methods: This is an observational study over an 11-year period in Poitiers University Maternity, France. We included women with vaginal operative deliveries after 34 gestational weeks for singleton births in cephalic presentation. We collected data on the mother and operative delivery characteristics: indication, instrument, epidural analgesia, labor length, episiotomy, OASI, and birthweight. We investigated the changes in the mediolateral episiotomy (MLE) and OASI rates and the association between MLE and OASI. The primary outcome was the evolution of the OASI and MLE rates. The secondary outcome was the occurrence of OASI during operative delivery with or without MLE.

Results: In total, 2357 operative deliveries were assessed, including 847 vacuum-, 1350 forceps- and 160 spatula-assisted deliveries. Of these, 950 were performed with MLE and 1407 without; 37 OASIs (3.9%) occurred in the MLE group, and 137 (9.7%) in the no-MLE group. Between 2005 and 2015, MLE use decreased from 78.5 to 16.2% and OASI occurrence increased from 3.1 to 12.7%. The increase in OASI occurrence was significant for forceps deliveries, but not for vacuum or spatula deliveries. Operative delivery with MLE was associated with a three times lower OASI occurrence than that without MLE (adjusted OR = 0.29, 95% CI [0.20-0.43]).

Conclusions: Implementation of a restrictive MLE policy for operative delivery seems to be associated with an increase in OASI incidence with forceps, but not with vacuum.

Keywords: Childbirth; Episiotomy; Instrumental delivery; Obstetric anal sphincter injury; Perineal trauma.