Causes of jaundice in newborns

In newborns, jaundice is caused by the normal breakdown of red blood cells. This process releases a chemical called bilirubin, which makes the skin go yellow.

Babies break down red blood cells very quickly, but their livers aren’t developed enough to get rid of bilirubin. This results in a bilirubin overload, which makes babies’ skin and eye whites go yellow.

Breastmilk jaundice
Most newborns with jaundice will have ‘breastmilk jaundice’. This is when a chemical in the mother’s breastmilk interferes with getting rid of bilirubin. This type of jaundice usually sorts itself out without treatment, after several weeks.

Blood type incompatibility jaundice
One rare type of jaundice happens when the mother’s and the baby’s blood groups are incompatible. This is usually ABO blood type or Rh-type incompatibility.

This isn’t usually a problem during a first pregnancy because the mother’s and the baby’s bloodstreams don’t mix. But during the delivery, some of the baby’s blood might mix with the mother’s blood. The mother then develops antibodies that become active during her next pregnancy and cross the placenta to attack a second baby’s red blood cells.

Their destruction releases bilirubin into the second baby’s bloodstream, which results in jaundice. If this happens, you usually see it in the first 24 hours after birth.

Biliary atresia
Biliary atresia is a rare cause of jaundice in babies.

It happens when the tiny tubes that carry bile from the liver to the intestine get scarred. Babies with this condition usually grow normally and look well at first, but they get very ill with serious liver disease if they aren’t diagnosed and treated early.

These babies might also have pale-looking poo.

This type of jaundice doesn’t go away after two weeks of age as newborn jaundice does.

Symptoms of jaundice in newborns

Newborn jaundice causes your baby’s skin and the whites of her eyes to go a yellow colour. The jaundice typically starts on the face and head.

If the level of bilirubin increases, the colour spreads to the body. Your baby might also be drowsy and have feeding difficulties.

When to see your doctor about newborn jaundice symptoms

Newborn jaundice is usually harmless, but a nurse or doctor should check and monitor all cases of jaundice in newborns. Some babies have severe jaundice, which very occasionally can lead to deafness and even brain damage if not treated promptly.

You should take your baby to the doctor if:

  • your baby is unwell, feeding poorly and not gaining enough weight
  • your baby’s poo becomes pale or your baby’s wee becomes dark
  • your baby develops jaundice in the first 48 hours after birth
  • the jaundice becomes more noticeable after a week
  • the jaundice hasn’t gone away after two weeks.

Tests for jaundice in newborns

If your baby has jaundice lasting more than two weeks – especially if his poos are pale or his wees are dark – he’ll need a blood test to check the ‘conjugated bilirubin’ levels in his blood. Your baby might then need more tests on his liver.

Treatment of jaundice in newborns

Treatment for newborn jaundice depends on how bad it is and what has caused it.

Babies who develop jaundice several days after birth usually just need careful monitoring, sometimes with heel prick blood tests, to check the bilirubin levels in their blood.

If your baby’s bilirubin levels are high, she might have phototherapy treatment for a few days. This treatment uses ultraviolet light to help to break down the bilirubin overload. Your baby will be placed naked in a cot under a blue phototherapy lamp for 2-3 days. Her eyes will be covered for protection.

Most babies cope with phototherapy treatment well. Phototherapy has minimal side effects, although your baby might have a mild rash and runny poo for a few days. Some babies have small fluid losses during phototherapy, so they might need extra feeds at this time.

Severe jaundice, in which bilirubin levels are very high, might need treatment with an exchange transfusion. This is when a baby’s own blood is replaced with compatible fresh blood. This isn’t common.

If your baby has breastmilk jaundice, it doesn’t mean that you need to stop breastfeeding. This type of jaundice is usually mild and should get better by itself with time. Talk to your child and family health nurse or doctor if you’re worried about what to do.

Prevention of jaundice in newborns

Only ‘incompatible blood type’ jaundice caused by Rh-type incompatibility is preventable.

If your doctor or health professional thinks this type of jaundice might be a problem, you’ll get an anti-D injection immediately after delivery. This can prevent complications in subsequent pregnancies.