Anorectal malformations (ARMS) are also known as imperforate anus (IA). This is an "umbrella term" for a group of birth defects which affect the anorectal area.

During a normal bowel movement, solid waste passes from the colon (large intestine) to the rectum (the final section the colon) and through the anus. When a child has an ARM, the rectum and the anus do not develop properly.

Some types of ARM can cause constipation, fecal and / or urinary incontinence, infections and other problems. Some of these problems are very minor and easy to treat, with great long-term prognosis. Others are complex and affect multiple areas of life, such as sexual function and urinary and bowel control.