Outcomes Following Obstetric Anal Sphincter Injury: Is There a Difference Between Subtypes in the Short Term?

Area of Science:

• Urogynecology
• Obstetrics
• Pelvic Floor Disorders

Background:

• Obstetric anal sphincter injuries (OASI) occur in 2.9% of vaginal births, leading to significant maternal morbidity.
• Pelvic floor dysfunction is a common complication following OASI, impacting women's quality of life.
• Understanding the differential impact of OASI severity on pelvic floor outcomes is crucial for patient management.

Purpose of the Study:

• To compare pelvic floor dysfunction outcomes between women with minor OASI (grade 3a) and major OASI (grades 3b, 3c, and 4).
• To evaluate differences in bowel and urinary symptoms, pelvic floor muscle strength, and Pescatori scores based on OASI severity.

Main Methods:

• Prospective data collection from 2011-2023 in a tertiary Urogynaecology centre, including 1327 women with complete data.
• Patients were assessed in a perineal clinic, with data on bowel/urinary symptoms (0-4 scale), pelvic floor muscle (PFM) strength, per rectal (PR) squeeze, and Pescatori scores.
• Retrospective comparison of outcomes between minor (n=639) and major (n=688) OASI groups using chi-squared and Mann-Whitney U tests.

Main Results:

• No significant differences were observed in faecal passive incontinence, flatal incontinence, or urinary symptoms at 3 months postpartum between minor and major OASI groups.
• Pelvic floor muscle strength, Pescatori scores, and PR squeeze assessments showed no significant differences between the groups.
• A statistically significant difference was found for fecal urgency (2.8% vs 5.1%, p=0.0045) and fecal urgency incontinence (0.2% vs 1.2%, p=0.003), with higher rates in the major OASI group.

Conclusions:

• Women with minor OASI experience significantly less fecal urgency and urgency incontinence compared to those with major OASI.
• Overall pelvic floor dysfunction, including other bowel and urinary symptoms, did not differ significantly between minor and major OASI groups.
• Further prospective studies utilizing validated questionnaires and long-term follow-up are recommended to confirm these findings.