Anorectal Malformation

Anorectal malformation occurs in approximately 1 out of every 5,000 births. It is a birth defect in which the anus and rectum do not develop the correct way.

In a fetus, the large intestine and the urinary tract begin as one large mass of cells that usually separate during the 7th to 10th week of pregnancy. In anorectal malformation, the anal passage is narrow and the rectum is not connected to the anus. The rectum may be connected to the urinary tract or reproductive system.

Often there is a membrane covering the anal opening. If the anal passage is narrow, it will be hard for the child to have a bowel movement. If there is a membrane covering the anal opening, a bowel movement is generally not possible.

The cause is usually unknown, although some studies have shown that a recessive gene can be the cause. A child that has anorectal malformation may also have abnormalities in their digestive system , urinary tract or spine. Occasionally this can be seen on a prenatal ultrasound, but the majority of cases are diagnosed immediately after birth when a nurse is trying to take a rectal temperature or in the absence of a bowel movement.

Doctors diagnose this when a child is born through physical examinations, abdominal x-rays, ultrasounds and CAT scans. Surgery is usually the only corrective treatment for the defect and long term prognosis is generally good.