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Obstetric anal sphincter injury - Prospective evaluation of incidence

Varma, Aarti; Gunn, James; Gardiner, Angela; Lindow, Stephen W.; Duthie, Graeme S.


Aarti Varma

James Gunn

Angela Gardiner

Stephen W. Lindow

Graeme S. Duthie


PURPOSE An obstetrically damaged anal sphincter is the principal cause of the development of fecal incontinence in otherwise healthy females. Reports suggest that such damage complicates as many as 35 percent of primiparous vaginal deliveries, with 13 percent of first-time mothers becoming symptomatic. In maternity units delivering 3,000 patients annually, it would follow that 390 symptomatic patients would develop new symptoms each year. This incidence of dysfunction does not reflect current clinical practice. We have investigated this discrepancy to establish the actual incidence of anal sphincter trauma associated with childbirth. METHODS During a six-week period, 159 females (105 primiparous and 54 para-I) were prospectively assessed postnatally using a standardized symptom questionnaire, endoanal ultrasound, and anal manometry. This group constituted 84 percent of all eligible deliveries occurring in the unit during the study period. RESULTS One patient developed fecal urgency after this delivery; there were no reports of fecal incontinence. Anal sphincter injuries were identified ultrasonically in 6.8 percent of primiparous patients, 12.2 percent of para-I patients having vaginal deliveries, and 83 percent of patients having forceps deliveries overall. Manometric data provided confirmatory evidence, with significantly reduced maximum squeeze pressures in patients with a disrupted anal sphincter (P<0.0005). CONCLUSIONS A symptom questionnaire is inadequate to identify anal sphincter injuries. The incidence of sphincter injury in relation to vaginal delivery has been overestimated in previous published work. This study demonstrates that the true incidence is 8.7 percent overall and that symptoms of sphincter dysfunction are uncommon this is in keeping with current clinical practice.


Varma, A., Gunn, J., Gardiner, A., Lindow, S. W., & Duthie, G. S. (1999). Obstetric anal sphincter injury - Prospective evaluation of incidence. Diseases of the colon & rectum, 42(12), 1537-1542.

Journal Article Type Article
Acceptance Date Dec 1, 1999
Publication Date 1999-12
Journal Diseases of the colon and rectum
Print ISSN 0012-3706
Electronic ISSN 1530-0358
Publisher Springer Verlag
Peer Reviewed Peer Reviewed
Volume 42
Issue 12
Pages 1537-1542
Keywords Gastroenterology; General Medicine
Public URL
Publisher URL
PMID 10613471