Biliary Atresia

Biliary Atresia

Biliary atresia is a rare but serious liver disorder that affects newborn pēpi (babies).

Illustration by Dr Greta File. Property of KidsHealth.

Illustration showing biliary atresia compared with a normal biliary system in a baby


Key points about biliary atresia

  • biliary atresia is a rare but serious liver disorder that affects newborn pēpi
  • biliary atresia causes jaundice that continues after 2 weeks of age in newborn pēpi
  • pēpi need special tests to diagnose biliary atresia
  • treatment involves surgery as early as possible to minimise liver damage
  • the surgery is not always successful
  • if the liver is badly damaged, a liver transplant may be necessary

What is biliary atresia?

Biliary atresia is a condition that happens when irritation and swelling (inflammation) develop in the bile ducts of infants. The inflammation can happen in any of the bile ducts inside and outside the liver. This causes bile duct damage. 

When the ducts are damaged, the bile cannot flow out of the liver. Bile is trapped and causes scarring of the liver. This scarring is called fibrosis. The bile ducts outside the liver are always permanently damaged preventing any bile flow into the gut. The gall bladder is also affected.

What causes biliary atresia?

The cause of biliary atresia is not known. There is currently no known way of preventing biliary atresia, or of predicting when it will occur.

What are the early signs of biliary atresia?

In the first few weeks of life, pēpi with biliary atresia often seem well apart from having yellow skin and whites of the eyes. This yellow colour is called jaundice. Most pēpi with jaundice are healthy and the jaundice fades over the next few weeks. In biliary atresia, the jaundice does not fade or it gets worse over time.

The following are important signs to look out for. 

Dark wee

A baby's wee should not have any colour.

Pale poo

White, cream, grey or beige-coloured poo. Baby poo is normally green or yellow.


Bleeding that lasts longer than normal. Common places pēpi can bleed from are the nose or mouth.

When should I seek help for my baby with jaundice?

You should see a health professional or lead maternity carer (LMC) if your baby:

  • is still jaundiced at 2 weeks of age
  • becomes jaundiced after 2 weeks of age
  • has pale, white or light beige-coloured poo 
  • has yellow or dark wee

The photo below shows a nappy with pale poo and dark wee.

Nappy with dark urine and light colours stool from liver disease

How is biliary atresia diagnosed?

There are many reasons why your baby might be jaundiced after the age of 2 weeks. A health professional, midwife or LMC should check your baby. A health professional, midwife or LMC should ask for a blood test to help find the reason for the jaundice. Biliary atresia is very rare, so the blood test may show another cause for the jaundice.

If the health professional suspects biliary atresia, they will make an urgent appointment for your baby with a paediatrician (a specialist in children's health). 

Your baby may have:

  • more blood tests
  • an ultrasound scan of the liver
  • a liver biopsy 

See the KidsHealth page on ultrasound scans for children for more information.

See the KidsHealth page on liver biopsy for more information.

How is biliary atresia treated?

The treatment for biliary atresia is a surgery called the Kasai procedure. The surgery involves connecting part of the intestine directly to the liver so that bile is able to flow from the liver to the intestine.

The picture below shows a normal biliary system.

The picture below shows the missing bile ducts in biliary atresia and the Kasai procedure which is used to treat biliary atesia.


Illustration showing Kasai procedure used for biliary atresia

This operation works best if your baby is young (less than 2 months old). The operation does not always cure biliary atresia, even when it is done early.

If the operation does not help, then over time your child's liver will become more and more damaged. This leads to liver failure. The only cure for liver failure is a liver transplant.

What are the complications of biliary atresia?

Biliary atresia can cause a number of problems.

Growth problems

Your baby will not be able to digest the fats from breastmilk or normal formula milk because bile (needed for fat digestion) is not getting into the intestine. This leads to poor growth. Your baby may need a special feed that contains a different kind of fat, that they can digest better. Some pēpi need extra feeds or supplements through a feeding tube to help them grow.

Vitamin deficiencies

Vitamins A, D, E and K dissolve in fat so they cannot be absorbed properly into the body in biliary atresia. Your baby will need extra medicine to provide these vitamins.


Liver disease may cause a baby to be very itchy. This problem does not affect all pēpi with jaundice, but it can be quite distressing. Your baby may need medicine to help with the itch.

Other problems

If the Kasai surgery is unsuccessful and the liver starts to fail, other problems may occur. Your specialist team will talk to you about the risks for your baby and the things to watch out for.


Illustrations by Dr Greta File. Property of KidsHealth. 

Photo of nappy with pale poo and dark wee provided by Dr Helen Evans. 

This page last reviewed 19 March 2024.

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