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Imperforate anus

  • Definition

    Imperforate anus is congenital (present from birth) defect in which the opening to the anus is missing or blocked. The anus is the opening to the rectum through which stools leave the body.


    Alternative Names

    Anorectal malformation; Anal atresia


    Causes, incidence, and risk factors

    Imperforate anus may occur in several forms. The rectum may end in a blind pouch that does not connect with the colon. Or, it may have openings to the urethra, bladder, base of penis or scrotum in boys, or vagina in girls. A condition of stenosis (narrowing) of the anus or absence of the anus may be present.

    The problem is caused by abnormal development of the fetus, and many forms of imperforate anus are associated with other birth defects. It is a relatively common condition that occurs in about 1 out of 5,000 infants.