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Anorectal Malformation

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An anorectal malformation (ARM), commonly called imperforate anus, is a birth defect in which the anus and rectum do not develop properly, and your baby is born with a blocked or misplaced anal opening. The condition affects how your child stools through the lower digestive tract.

Frequently Asked Questions About Anorectal Malformations

What types of anorectal malformation are found in children?

If your child has an anorectal malformation, several problems can occur, including:

The anal passage may be narrow
The anal opening may be covered with tissue or a membrane (thin barrier)
The anal opening may not be in the right place
The anal opening may not be lined up with the anal muscles
There may be an abnormal connection (fistula) between the rectum and the urinary tract or reproductive organs

Anorectal malformation may appear differently in boys and girls.

Girls can have an anus that is anterior, meaning it is not in the correct place. The most common form in girls is recto-vestibular fistula, when the anal opening connects to the vagina. Cloaca is the rarest and most complex anorectal malformation in girls. It occurs when the urethra, vagina and anus share one opening.

Boys can also have an anus in the incorrect place. Boys could also have an abnormal connection between the anal opening and the bladder or urethra.

What are the symptoms of anorectal malformation?

Anorectal malformations cause problems with a child’s bowel movements. Your baby may have symptoms including:

Lack of stool
Stool coming from the vagina
Trouble having a bowel movement
Chronic constipation in older children

Most anorectal malformations are found before a newborn leaves the hospital.

When should you seek help for anorectal malformation?

If your baby was not diagnosed with an ARM, but is experiencing the following symptoms, call your health care provider.

Passes stool from her vagina
Passes urine from the anus
Inability to poop
Chronic constipation

If your baby is not having any bowel movements, seek emergency care immediately.

What causes anorectal malformation?

In most cases, the cause of the condition is unknown.

As a baby grows in its mother’s womb, the baby’s lower part of the large intestine and the urinary tract start off as one channel. The rectum and anus then separate from the urinary tract. When these steps don’t happen as they should, the rectum or anus may not develop normally.

Anorectal malformation sometimes occurs with certain genetic syndromes or other birth defects. These include:

VACTERL association, which includes problems with the spine, anus, heart, trachea, esophagus, kidneys and limbs
Digestive system problems
Urinary tract problems
Spinal problems
Down syndrome
Townes-Brocks syndrome. This condition includes problems with the anus, kidneys, ears, and arms and legs.

How is anorectal malformation diagnosed?

An anorectal malformation is usually diagnosed at birth if the anal opening isn’t present or is in the wrong place. An anorectal malformation is occasionally diagnosed prenatally.

Your child’s health care provider will do a physical exam when your baby is born. The provider will examine your child’s anus to see if it is open. In order to better understand the anorectal malformation your child may also have imaging tests such as:

Abdominal X-rays to take images of internal tissues, bones, and organs
Renal ultrasound, a test that uses sound waves to make images of the kidneys, uterus and bladder.
Spine ultrasound, a test used to examine the spine
Babygram, which is a full body X-ray of your baby
Echocardiogram, a test that uses ultrasound to make images of the heart.

How is anorectal malformation treated?

Treatment will depend on your child’s symptoms, age and general health. It will also depend on the severity of the condition.

Most babies with ARM will need surgery to correct the problem. The type and number of surgeries your child needs will vary, depending on his or her condition.

In addition, children with anorectal malformation receive specialized, multidisciplinary care by the CHOC Colorectal-Bowel Management Program.

CHOC Pediatric Procedures for Anorectal Malformation

Pull-through procedure. This surgery is called posterior sagittal anorectoplasty (PSARP), also called the Peña Procedure. In this operation, your baby’s rectum will be repositioned in the correct location and an anal opening will be created. This surgery is done under general anesthesia and is performed in the first days of life for babies who are full-term and healthy. A few weeks after surgery, your doctor will ask you to do anal dilations, an after-care procedure to help keep the new opening from tightening up or scarring closed.

Colostomy. In some cases, a colostomy may need to be performed before the pull-through procedure is done. It is often done if your baby is small, premature, has other medical problems or if their anorectal malformation is complex. A colostomy is a surgical procedure that reroutes the large intestine to an opening made on the abdomen. A colostomy is usually temporary and will be reversed. It does not damage your child’s ability to eat or poop—instead, it allows your child to feed and grow before corrective surgery is done later. The nursing staff and other health care professionals that work with your child’s surgeon are here to help you learn to take care of the colostomy.

What to Expect After Anorectal Surgery

Post-surgery diet. Your baby can eat soon after surgery. A few weeks after surgery, stools are passed less often and are more solid. This often causes constipation. Your child’s health care provider may recommend a high-fiber diet to help with constipation. This includes fruits, vegetables, juices, whole-wheat grains and cereals, and beans.

Closing the colostomies. If your baby had a colostomy, this will be reversed several months later. After this surgery, your child will not be able to eat anything for a few days. This lets the intestine heal. Once they start pooping through the anus and rectum, they can return to regular food. For older infants who have never stooled through the anus and rectum, diaper rash can commonly occur. This usually resolves after a few days. Your child’s doctor can help you manage this skin irritation.

Bowel movements and toilet training. Most children can toilet train at the usual age. Our goal is for them to be fully continent. However for some children whose anorectal malformation is very complex, this may be more difficult. Your surgeon and gastroenterologist will help you understand what to expect and how best to help your child, including a referral to a bowel management program.

Constipation. Children who have had surgery for anorectal malformation are likely to experience constipation for the long term. They may require gentle medication such as stool softeners or laxatives to help them poop. A high-fiber diet is also important for these children. Your child’s surgeon and gastroenterologist will help you manage constipation.

Why Choose CHOC for Pediatric Surgery

All pediatric surgical procedures require additional training and expertise, but the anorectal organs on babies are so small, delicate and intricate that they demand the most experienced surgeons and staff available. This is even more essential for babies who are born prematurely.

The CHOC Surgical Neonatal Intensive Care Unit (NICU) follows a coordinated care plan for babies, bringing all providers on the baby’s care team together and providing a seamless experience for families. This coordinated approach is tested by national-level research and quality improvement efforts, leading to better outcomes in many cases.

Pediatric surgeon smiling and holding infant boy