Anorectal Malformations

What are anorectal malformations?

Anorectal malformations are birth defects in which the anus and rectum (the lower end of the digestive tract) don’t develop properly. They occur in an estimated 1 in 4,000 newborns and can range from mild to complex.

Anorectal malformations include several different abnormalities, including:

  • The anal passage may be narrow.
  • A membrane may be present over the anal opening.
  • The rectum may not connect to the anus (imperforate anus).
  • The rectum may connect to a part of the urinary tract or the reproductive system through an abnormal passage called a fistula.

Types of Anorectal Malformations

Anorectal malformations, including imperforate anus, can affect male and female babies in different ways. 

In boys, the main anorectal malformations are perineal fistula, rectobulbarurethral fistula, rectoprostatic fistula and rectobladderneck fistula. 

Perineal Fistula
Rectobulbarurethral Fistula
Rectoprostatic Fistula
Rectobladderneck Fistula


In girls, the main anorectal malformations are rectoperineal fistula, rectovestibular fistula and cloaca.

Perineal Fistula
Rectoperineal Fistula
Rectovestibular Fistula


A type of anorectal malformation called imperforate anus can occur in both boys and girls.

Imperforate Anus

How we care for anorectal malformations

Anorectal malformations can be complex issues. The Colorectal and Pelvic Malformation Center at Boston Children’s Hospital includes a comprehensive team of colorectal surgeons, urologists, gynecologists and gastroenterologists who evaluate the problem using advanced diagnostic tests and then provide a coordinated plan of care for children with anorectal malformations such as imperforate anus. Because the surgery is only the first step for many of these children, the center not only offers reconstructive surgical care, but lifelong management of bowel, bladder and reproductive issues as well.

We offer therapies that are limited to only a few centers around the world, such as:

  • bowel management program
  • peristeen counseling
  • sacral nerve stimulation

Our team also includes nutritionists, psychologists and other experts to improve the quality of life for each child entrusted to our care.