Obstetric anal sphincter injuries (OASIs) affect 6% of nulliparous women and 2% of parous women, with Asian race being a recognised risk factor for OASI.

The perineal clinic was established at Singapore’s largest maternity hospital in 2022 offering multidisciplinary care for women post-OASI. A dedicated urogynecologist and pelvic floor physiotherapist jointly reviewed patients at 3 to 6 months post-OASI. Pelvic floor physiotherapy, endoanal ultrasound and anorectal manometry were routinely offered to all patients who attended this service. 

This study aims to characterise patients seen at the new perineal clinic and determine short to medium term outcomes of women following OASI. It also aims to describe the utilisation of services in a new perineal clinic seeing women with recent or past history of OASI and to identify areas for improvement.

This retrospective audit of clinical notes included all patients seen at the perineal clinic between January 2022 to December 2023. Data was deidentified and aggregated, with analysis performed using SPSS. Institutional review board was not required for this study as this analysis was performed as an audit.

A total of 64 patients were seen in the perineal clinic during the study period. 2 patients referred due to past history of OASI in a previous birth and fistula-in-ano were excluded from analysis. Characteristics and distribution of OASI severity of the patients seen in the perineal clinic are shown in Table 1. The commonest grade of OASI was 3A (48.4%). 4th degree tears affected 9.7%. 

Prevalence of symptoms seen 3-6 months postnatally is shown in Table 2.

Advanced maternal age (≥35 years, 25%) was associated with increased severity of OASIs (p=0.046). 

The prevalence of flatus incontinence and faecal incontinence were both 17.7%. Patients also reported urinary incontinence (54.8%) consisting of stress urinary incontinence (37.1%), urgency urinary incontinence (8.1%) and mixed urinary incontinence (9.7%). Other symptoms included perineal pain (9.7%), sexual dysfunction (30.6%), and psychological issues (4.8%). There was 1 case of anorectal fistula (1.6%). 

A 60.9% increase in physiotherapy adherence was observed after attendance of the combined perineal clinic. Most patients were discharged from the perineal clinic during their first visit (82.3%), with 17.7% receiving referrals to other specialists (e.g., colorectal, gynaecology) or combined clinics (pelvic floor clinic). In this cohort, 5 women who were recommended for vaginal delivery following previous OASIs had successful births with no further OASI.

Overall, we conclude that this combined perineal clinic offers an opportunity for intervention as a significant number of women suffer bothersome short to medium term symptoms post-OASI. Notably, the adherence to physiotherapy is markedly improved after attendance of the perineal clinic. Following thorough assessment and counselling for subsequent pregnancies, women who were suitable for vaginal birth were also able to achieve uncomplicated deliveries without further OASI.

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Wan, O. Y. K., Taithongchai, A., Veiga, S. I., Sultan, A. H., & Thakar, R. (2020). A one-stop perineal clinic: our eleven-year experience. International urogynecology journal, 31(11), 2317–2326. https://doi.org/10.1007/s00192-020-04405-2
Royal College of Obstetricians and Gynaecologists (2015) The management of third- and fourth-degree perineal tears. Green-top guidelin no. 29. https://www.rcog.org.uk/globalassets/documents/guidelines/gtg-29.pdf.