Anal function: effect of pregnancy and delivery.

OBJECTIVE: To investigate the effect of pregnancy and delivery on anal continence, sensation, manometry, and sphincter integrity.

STUDY DESIGN: Two hundred eighty-six nulliparous women in the third trimester completed a symptom questionnaire and underwent anorectal sensation and manometric evaluations. Three months postpartum, 161 women returned and the questionnaires and investigations were repeated together with anal endosonographic examinations.

RESULTS: The prevalence of fecal urgency before, during, and after pregnancy was 1%, 9.4%, and 10.5%, respectively; the prevalence of anal incontinence before, during, and after pregnancy was 1.4%, 7.0%, and 8.7%, respectively. Vaginal delivery, particularly instrumental, resulted in a decrease in anal squeeze pressures (P =.015) and resting pressures (P =.002) but had no effect on anal sensation. Postpartum anal endosonographic examination revealed sphincter disruption in 38% of women. There was no relationship between symptoms and anal manometry, sensation, or sphincter integrity. Vaginal delivery (P <.0001) and perineal trauma (P <.001) were significantly associated with sphincter defects.

CONCLUSION: Vaginal delivery is associated with a decrease in anal pressures and increased anal sphincter trauma but has no effect on anal sensation. These changes were not related to anal symptoms.