​​DISCLAIMER: The following information has been gathered from various sources, including Medical Professionals and experts in the field. This is in no way a medical text, but can be used as a helpful set of information that will hopefully give you an understanding and basic knowledge of the subject.
What is Anorectal Malformation/ Imperforate Anus?
ARM - Anorectal Malformation / IA - Imperforate Anus.
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Anorectal Malformation (ARM) is a condition that affects the rectum and the anus.
It develops during the very early stages of pregnancy, while the baby is forming in the womb.
In babies with ARM, the anus may not have formed properly, may be in the wrong position, or may be absent altogether.
As a result, faeces (poo) may be unable to leave the body or may pass through the vagina or the urethra (the tube that allows urine/wee to exit the bladder from your body) instead.
Around 1 in 4500 babies are born with ARM, although some recent research suggests that it is closer to 1 in 2850(1).
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In real terms, each region expects there to be between 5-10 babies born with ARM each year. ARM is a fairly rare condition, but it is important to remember that you and your family are not alone.
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“We do not know exactly what causes this, but it is not due to anything that happened during pregnancy. Research has indicated some possible causes of anorectal anomaly but none are certain and these need further investigation”.(2)
It is important for parents to know that they are not responsible for their baby’s ARM.
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References:
(1) Kathryn Ford et al. Archives of Disease in Childhood, 2022
(2)Anorectal anomaly | Great Ormond Street Hospital
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November 2025 Reviewed by
Jonathon Sutcliffe. Consultant Paediatric Surgeon. Leeds Teaching Hospital NHS Trust.
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