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Imperforate Anus

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What Is an Imperforate Anus?

An imperforate anus happens when the anus is missing or doesn't have a hole. The anus is the muscle ring that lets a person hold poop inside, then release it later during a bowel movement (BM). Imperforate anus is a type of birth defect called an anal malformation. This means that the anus and rectum don't form in the usual way. Anal malformations have different effects in boys and girls.

A baby born with an imperforate anus has problems with:

  • the anal opening, where poop leaves the body
  • the rectum, the section of large intestine above the anus
  • the nerves that tell the body when it's time to have a BM

This means the baby has trouble having normal BMs.

What Causes an Imperforate Anus?

Doctors don't know exactly what causes an imperforate anus (im-PER-fer-it AY-nus).

A baby's digestive tract forms during early pregnancy. After birth, whatever a baby eats that's not absorbed by the digestive tract turns into poop (feces or stool). Then it passes out of the body through the anus. The anal sphincter (SFINK-tur) is a group of muscles in the anus that controls the release of poop. In an imperforate anus, the anal sphincter usually forms in the right place, but without the normal opening. When this happens, the rectum might be:

  • covered by tissue or a membrane
  • open in the wrong place

What Are Some Types of Imperforate Anus?

An anus that forms without an opening is called anal atresia

Another type of anorectal malformation, when the rectum opens in the wrong place, has different names, depending on the parts of the body affected:

  • A rectoperineal fistula (opening) on the skin behind the genitals (an area called the perineum).
  • Boys may have a rectourethral fistula, which connects the rectum to the urethra, the urine (pee) tube. Both pee and poop come out of the urethra's opening, which is usually at the tip of the penis.
  • In girls, the rectum may open in:
    • the vagina (rectovaginal fistula)
    • the area around the vaginal opening (rectovestibular fistula)
    • a cloaca (klo-AY-kuh), which is a single opening that connects to the rectum, vagina, and urethra (the urine tube)

What Are the Signs & Symptoms of an Imperforate Anus?

When a baby is born with an imperforate anus, the baby's doctor or parent may notice:

  • The baby's anus is missing or in the wrong place.
  • The baby doesn't poop within 48 hours of birth.
  • The baby's belly is swollen.
  • Poop (stool or feces) comes out at the wrong place, such as the:
    • vagina or skin near the opening of the vagina in girls
    • scrotum, the base of the penis or its tip in boys

How Is an Imperforate Anus Diagnosed?

In some cases, an ultrasound before birth may show things that suggest an imperforate anus.

The diagnosis of imperforate anus is almost always made after birth. Doctors may use tests to learn more about how the baby's parts formed, including:

  • X-rays of the stomach area to look at the esophagus and bones of the spine
  • ultrasound (using sound waves to see inside the body) scans of the kidneys, pelvis (lower part of the belly), and spinal cord
  • magnetic resonance imaging (MRI) to check the spine and pelvis
  • echocardiogram to check the heart

How Is an Imperforate Anus Treated?

A surgeon and other specialists usually treat a baby with an imperforate anus. Treatment right after birth often includes:

  • placing a tube through the baby's nose into the stomach (a nasogastric, or NG, tube) to keep the stomach empty
  • giving the baby intravenous (IV) fluid
  • making a treatment plan based on how the baby's anus and other parts formed

Most infants with imperforate anus will need surgery to fix the problem.

A common repair is a posterior sagittal anorectoplasty (PSARP). It's done when the surgeon knows the location of the organs in the abdomen and where the rectum ends. The doctor will make an incision (cut) between the baby's butt cheeks, then disconnect the rectum from the urinary tract or vagina and place it within the anal sphincter. At some point, the baby might need a temporary colostomy. Colostomy means that the bowel movement (poop) goes into a bag that is outside the skin.

What Else Should I Know?

Many children with imperforate anus will have trouble with pooping. Some may have trouble holding their urine. Routine visits with the doctor can help with these issues.

A continence clinic (a clinic that treats children who have bowel or bladder problems) can help children and families overcome the physical, mental, and social challenges that may follow the surgical repair of an imperforate anus.

Being involved in your child's care plan can help you feel more in control:

  • Take things one day at a time.
  • Look to your care team to guide you on caring for your child, getting ready for surgery, recovery, and more. If you have questions, ask.
  • Accept help when you can, and lean on those around you for support.

You also can find more information and support online at:

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Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

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