Decreased anal sphincter lacerations associated with restrictive episiotomy use

To determine whether restrictive episiotomy use was associated with decreases in anal sphincter lacerations and the risk of anal sphincter laceration attributable to episiotomy.

This was a retrospective database study. Rates of episiotomy, anal sphincter laceration (third- or fourth-degree tear), and other confounding variables were compared among vaginal deliveries before (1999) and after (2002) restrictive episiotomy use was implemented at our institution. Logistic regression was used to estimate the odds ratio of anal sphincter laceration that was due to episiotomy and other variables.

The episiotomy rate decreased 56% (37% to 17%, P < .001) between 1999 and 2002, whereas the anal sphincter laceration rate decreased 44% (9.7% to 5.4%, P < .001). There were no changes in age, race, nulliparity, prolonged second stage of labor, operative vaginal deliveries, birth weight, or macrosomia, although oxytocin use and epidural use decreased slightly (37% to 31%, P < .001, and 80% to 76%, P = .02, respectively). The adjusted odds ratio of anal sphincter laceration attributable to episiotomy decreased 55%, from 6.5 (95% CI: 3.8, 11.1) to 2.9 (95% CI: 1.7, 5.0), between 1999 and 2002. Conversely, the adjusted odds ratios of anal sphincter laceration attributable to the other independent risk factors all increased or remained the same: operative vaginal delivery, which increased from 4.4 (95% CI: 2.7, 6.9) to 6.3 (95% CI: 3.6 11.1); nulliparity, from 2.9 (95% CI: 1.8, 4.8) to 2.9 (95% CI: 1.4, 5.9); macrosomia, from 1.9 (95% CI: 1.1, 3.4) to 2.6 (95% CI: 1.3, 5.4); and prolonged second stage, from 2.0 (95% CI: 1.3, 3.0) to 2.1 (95% CI: 1.2, 3.7).

With restrictive episiotomy use, the episiotomy rate, anal sphincter laceration rate, and risk of anal sphincter laceration attributable to episiotomy were all reduced by approximately 50%.