VAGINAL DELIVERY IS ASSOCIATED WITH OCCULT DISRUPTION OF THE ANAL-SPHINCTER MECHANISM

Childbirth is thought to be an important cause of pelvic floor dysfunc tion. Heretofore, this has been thought due to pudendal denervation. E ndovaginal sonography allows thorough assessment of the anorectum and in this study was used to assess nulliparous women and women before an d after delivery. Two groups were studied. Thirty-two nulliparous subj ects without complaints of incontinence were studied once. Thirty-four pregnant women were studied before and after delivery. Endovaginal so nography was used to assess integrity of intern I and external anal sp hincters, thickness of the levator bundle, internal and external sphin cters, anal length, and the angle between the levator bundles. Deliver y was associated with disruption of the internal and external sphincte rs. No nulliparous women (nonpregnant or pregnant) had sphincter disru ption demonstrated. Episiotomy in the index delivery was associated wi th increased thickness in the external sphincter and a smaller angle b etween the levator bundles. Vaginal delivery is associated with occult disruption of the anal sphincters.