Obstetric anal sphincter injury in the UK and its effect on bowel, bladder and sexual function

To determine the incidence and factors associated with the development of bowel, urinary and sexual symptoms following obstetric anal sphincter injury (OASIS).

A prospective cohort study involving 435 women who sustained OASIS, over a five-year period, in a large UK teaching hospital. Details of bowel, urinary and sexual function were documented using a structured questionnaire. The outcome measures included the incidence of symptoms following OASIS and factors which modify the risk of developing symptoms.

The majority (96%) of women were faecally continent three months after primary OASIS repair. Nevertheless, 34.2% reported faecal urgency, 25% suffered poor flatal control, and nearly 30% reported pain and bleeding on defaecation. Sixteen percent of women reported stress urinary incontinence, 15% experienced urgency and 20% reported urinary frequency. Fifty-seven percent of women had resumed intercourse but 32% of those women reported dyspareunia. Women who developed faecal symptoms were significantly more likely to develop urinary symptoms. Advancing maternal age and the use of forceps, in particular rotational forceps, significantly increase the risk of developing faecal and urinary symptoms.

Obstetric anal sphincter injuries continue to be responsible for significant morbidity, with approximately 30% of women reporting faecal, urinary or sexual symptoms, three months postpartum. This large prospective UK study provides up-to-date information relating to factors which increase the likelihood of such symptoms occurring. These data are useful for counselling and targeting more intensive follow up to women at higher risk of developing symptoms.