Imperforate anus is a defect that is present from birth (congenital) 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.
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.
The rectum may have openings to the urethra, bladder, base of the penis or scrotum in boys, or vagina in girls.
There may be narrowing (stenosis) of the anus or no anus.
The problem is caused by abnormal development of the fetus. Many forms of imperforate anus occur with other birth defects. It occurs in about 1 out of 5,000 infants.
Anal opening very near the vagina opening in girls
Baby does not pass first stool within 24 - 48 hours after birth
Missing or moved opening to the anus
Stool passes out of the vagina, base of penis, scrotum, or urethra
Swollen belly area
Signs and tests
A doctor can diagnose this condition during a physical exam. Imaging tests may be recommended.
The infant should be checked for other problems, especially those affecting the genitals, urinary tract, and spine.
Surgery to correct the defect is needed. If the rectum connects with other organs, these organs will also need to be repaired. A temporary colostomy (connecting the end of the large intestine to the abdomen wall so that stool can be collected in a bag) is often needed.
Most defects can successfully be corrected with surgery. Most children with mild defects do very well. However, constipation can be a problem.
Children who have more complex surgeries still usually have control over their bowel movements. However, they often need to follow a bowel program, which includes eating high-fiber foods, taking stool softeners, and sometimes using enemas.
Some children may need more surgery.
Calling your health care provider
This disorder is usually discovered when the newborn infant is first examined. Call your health care provider if a child that was treated for imperforate anus has abdominal pain or fails to develop any bowel control by the age of 3.
As with most birth defects, there is no known prevention.
Warner BW. Pediatric surgery. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 71.
Klein MD, Thomas RP. Surgical conditions of the rectum, anus, and colon. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 341.
Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.