Role of Selective Use of Mediolateral Episiotomy in Preventing Obstetric Anal Sphincter Injuries: A Critical Investigation

Recent study investigated the role of mediolateral episiotomy in preventing obstetric anal sphincter injuries (OASIs) during vaginal deliveries (VD) and vacuum-assisted deliveries (VAD) in nulliparous women. The primary outcome measured was the incidence of OASIs, with secondary outcomes including postpartum hemorrhage (PPH) and neonatal outcomes. The study was retrospective and approved by the local Institutional Review Board, with informed consent waived due to the study's design.

Statistical analysis involved propensity score (PS) matching to adjust for confounding factors in VD and VAD subgroups. Covariate balance was evaluated before and after matching to ensure effective control of potential confounders. The analysis used logistic regression, t-tests, chi-squared tests, and Fisher's exact tests to compare variables. Additionally, logistic regression analyses were performed to estimate odds ratios (ORs).

Patient Characteristics and OASIs Rates

The study included 22,738 patients, with an overall OASIs rate of 1.0%. Episiotomy rates were 38.5% for VD and 75.8% for VAD. In the VD subgroup, episiotomy did not significantly impact OASIs rates. In contrast, in the VAD subgroup, episiotomy showed a borderline significant protective effect against OASIs, which became statistically significant after adjusting for the duration of the second stage of labor.

Episiotomy Impact on Tears, PPH, and Neonatal Outcomes

Episiotomy was associated with reduced spontaneous tears in both subgroups but increased PPH rates. Neonatal outcomes did not significantly differ between episiotomy groups, except for a higher incidence of the composite neonatal outcome with episiotomy. Adjusted logistic regression analyses confirmed the protective effect of episiotomy against OASIs in VAD but not in VD. The study recommended a selective approach to mediolateral episiotomy, especially in VAD cases with prolonged second stages of labor, where it may offer protection against OASIs. The findings aligned with previous studies advocating for a restrictive episiotomy policy and selective use in specific clinical circumstances. Limitations included the retrospective design, potential underreporting of OASIs, lack of detailed episiotomy indication data, and variations in episiotomy practices among healthcare providers. Despite these limitations, the study's robust methodology, large sample size, and rigorous statistical analyses enhanced the reliability of its conclusions.

Implications for Future Research

The research highlighted the need for future studies to explore long-term outcomes of selective episiotomy, its impact on maternal well-being, and patient-centered outcomes. Understanding the specific clinical scenarios where episiotomy provides optimal benefit and its effects on different patient populations would further contribute to obstetric care guidelines.

Key Points

- The study examined the role of mediolateral episiotomy in preventing obstetric anal sphincter injuries (OASIs) in nulliparous women during vaginal deliveries (VD) and vacuum-assisted deliveries (VAD).

- Propensity score matching was used for statistical analysis to adjust for confounding factors in VD and VAD subgroups. Logistic regression and various statistical tests were employed to compare variables and estimate odds ratios.

- Among the 22,738 patients included in the study, the overall OASIs rate was 1.0%, with episiotomy rates of 38.5% for VD and 75.8% for VAD. Episiotomy did not significantly impact OASIs rates in the VD subgroup but showed a protective effect in the VAD subgroup after adjusting for the duration of the second stage of labor.

- Episiotomy was found to reduce spontaneous tears but increase postpartum hemorrhage (PPH) rates. Neonatal outcomes did not significantly differ between episiotomy groups, except for a higher incidence of the composite neonatal outcome with episiotomy.

- The study recommended a selective approach to mediolateral episiotomy, especially in VAD cases with prolonged second stages of labor, where it may offer protection against OASIs. The findings supported a restrictive episiotomy policy and selective use in specific clinical circumstances.

- Limitations of the study included its retrospective design, potential underreporting of OASIs, lack of detailed episiotomy indication data, and variations in episiotomy practices among healthcare providers. Future research should focus on exploring long-term outcomes of selective episiotomy, its impact on maternal well-being, and patient-centered outcomes to enhance obstetric care guidelines.

Reference -

O. Bercovich et al. (2025). Mediolateral Episiotomy And Obstetric Anal Sphincter Injuries In Nullipara: A Propensity Score Matching Study. *BMC Pregnancy And Childbirth*, 25. https://doi.org/10.1186/s12884-025-07184-0