by EBSCO Medical Review Board
(Imperforate Anus; Anorectal Malfunction)


Anal atresia is a problem with the way the anus forms and the part of the intestine leading to the anus. It can make it hard or impossible for the child to pass stool. A child may have:

  • An anal opening that is too thin or in the wrong place
  • A thin layer that covers the opening
  • Intestines that are not connected to the anus
  • An unusual link between the intestines and urinary systems that lets stool pass through the urinary system


Anal atresia happens when an unborn baby’s intestines develop the wrong way. The reason why is not known.

Risk Factors

Anal atresia is more common in boys. It is also more common in those with other health problems, such as Down syndrome and other birth defects.


Problems may be:

  • No anal opening at birth
  • Anal opening in the wrong place
  • No stool within 24 to 48 hours after birth
  • Problems feeding
  • Swollen belly

Mild anal atresia may not be found until later in life. It may show as a lack of bowel control by age 3 years.


The doctor will ask about your child's symptoms and health history. A physical exam will be done.

Images may be taken. This can be done with:


Surgery may be done to fix anal atresia. The type will depend on the defects that the child has. Examples are:

  • Surgery to connect the anus and intestine
  • Anoplasty to move the anus to the correct location
  • Colostomy to attach a part of the intestine to an opening in the wall of the belly to let waste to pass into a bag outside of the body
Temporary Colostomy of an Infant
exh5756b 97870 1 colostomy infant.jpg
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There are no guidelines to prevent this health problem.


Centers for Disease Control and Prevention 

Healthy Children—American Academy of Pediatrics 


About Kids Health—The Hospital for Sick Children 

Health Canada 


Anorectal malformations. EBSCO DynaMed website. Available at: Accessed November 2, 2020.

Imperforate anus. Cincinnati Children's website. Available at: Accessed November 2, 2020.

Gangopadhyay A, Pandey V. Anorectal malformations. J Indian Assoc Pediatr Surg. 2015 Jan-Mar;20(1):10-15.

Revision Information

  • Reviewer: EBSCO Medical Review Board Kari Kassir, MD
  • Update Date: 05/05/2021