Definition

Imperforate anus is a 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. This is present from birth (congenital).

Alternative Names

Anorectal malformation; Anal atresia

Causes

Imperforate anus may occur in several forms:

• The rectum may end in a pouch that does not connect with the colon.
• The rectum may have openings to other structures. These may include 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.

It is caused by abnormal development of the fetus. Many forms of imperforate anus occur with other birth defects.

Symptoms

Symptoms of the problem may include:

• Anal opening very near the vagina opening in girls
• First stool is not passed within 24 to 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

Treatment

A health care provider can diagnose this condition during a physical exam. Imaging tests may be ordered.

The infant should be checked for other problems, such as abnormalities of 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.

Outlook (prognosis)

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 have control over their bowel movements most of the time. However, they often need to follow a bowel program. This includes eating high-fiber foods, taking stool softeners, and sometimes using enemas.

Some children may need more surgery.

When to Contact a Medical Professional

This problem is often found when the newborn infant is first examined.

Call your provider if a child treated for imperforate anus has:

• Abdominal pain
• Constipation that is difficult to manage
• Failure to develop any bowel control by the age of 3

Prevention

There is no known prevention. Parents with a family history of this defect may seek genetic counseling.

References

Dingelsein M. Selected gastrointestinal anomalies in the neonate. In: Martin RJ, Fanaroff AA, Walsh MC, eds. Fanaroff and Martin's Neonatal-Perinatal Medicine. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 84.

Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Surgical conditions of the anus and rectum. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 371.