The natural history of clinically unrecognized anal sphincter tears over 10 years after first vaginal delivery

OBJECTIVE: To estimate the influence of clinically unrecognized anal sphincter injuries detected by endoanal ultrasonography 3 months after first vaginal delivery on symptoms of anal incontinence over the subsequent 10-year period. METHODS: One-hundred fifty-six consecutive primigravid women were recruited, anal endosonography performed, and bowel habit predelivery characterized by means of a validated 24-point questionnaire. After excluding four women with a clinically recognized sphincter tear after delivery and 18 who delivered by cesarean, these procedures were repeated 3 months postpartum. The questionnaire was repeated at 5 and 10 years to estimate continence change over the decade after delivery. Logistic regression was used to examine the effect of clinically unrecognized sphincter tears on continence. RESULTS: After delivery, continence deteriorated from baseline in 37 (28%) women, eight of whom had anal sphincter tears. Continence did not deteriorate in 97 women, six of whom had anal sphincter tears. At 10 years, 59 (55%) of 107 contactable women had continence scores greater than zero, 23 of whom had deteriorated from baseline. There was a significant relationship between a sphincter tear that was symptomatic after delivery and continence deterioration sustained at 5 and 10 years (odds ratio 2.8 for change in continence score). However, no relationship was found over 10 years for those women who sustained a sphincter tear but whose continence did not deteriorate postpartum. CONCLUSION: Ultrasonographic anal sphincter defects without postpartum incontinence are not associated with deterioration in continence over the following decade. LEVEL OF EVIDENCE: II.