If your child has been invited for a face-to-face appointment or procedure, it’s important you still come unless you hear otherwise.
To help keep everyone safe, only one parent or carer can attend. No other family or friends can visit.
See all our information about COVID-19, including steps we are taking to keep you safe.

Jaundice in new born babies

Your baby was referred because they are jaundiced. This website page explains what jaundice is and how it is treated.

What is jaundice?

Jaundice is a yellow colouration of the skin and whites of the eyes that is common in newborn babies.

It is caused by a pigment called bilirubin. Bilirubin is made from the breakdown of blood and is removed from the body by the liver. In newborn babies, blood breaks down more quickly so bilirubin levels can build up very high.

A moderate amount of jaundice is quite common in many newborns and not harmful. However, extremely high levels may be harmful, so this is why jaundice levels are monitored during the first few days of life to prevent the level getting too high.

Sometimes we need to treat the jaundice to stop the levels becoming high enough to make your baby unwell. As the liver begins to mature your baby will be able to clear these high levels by themselves. This should have happened by 2 weeks of age (3 weeks in premature babies).

How is jaundice monitored?

Midwives check babies for signs of jaundice by looking at the colour of their skin. As part of the assessment, they will also be asking about the baby’s wet and dirty nappies. If they notice jaundice they may use a machine (transcutaneous bilirubinometer) which measures the level of jaundice through the skin. In some cases they may ask one of the neonatal doctors to look at the baby, and possibly ask for a blood test to check the jaundice level.

How is jaundice treated?

Feeding helps babies to process the bilirubin, so it is important that jaundiced babies feed well and often, as the bilirubin is removed from the body when babies pass urine (pee). Jaundiced babies can be sleepy when feeding. If this happens, please ask the midwives for feeding support and advice.
Depending on the level of jaundice, your baby may need treatment by fluorescent lights, called phototherapy.

What is phototherapy?

Phototherapy is a light treatment used to breakdown the bilirubin which causes jaundice. On the postnatal ward this is done using a biliblanket. This is a pad your baby can lie on that produces light to help reduce the bilirubin. When using the biliblanket it is important to make sure the maximum area of light is in contact with your baby’s skin.

Contact us

If you have any questions or concerns about your baby’s jaundice while in hospital, ask the midwife looking after you and your baby. After transfer home, please contact your community midwife (contact details are in your discharge pack).

Phototherapy must be continued until the bilirubin level has dropped to a low and safe enough level. You should give your baby short breaks (up to 30 minutes) for nappy changing, feeding and cuddles. Blood tests are used to monitor your baby’s jaundice level.

Where will your baby receive phototherapy?

Most babies will have phototherapy on the postnatal ward, and sometimes there will be the option of having the phototherapy at home. For more information on having phototherapy at home, please see our leaflet, Phototherapy at home service.

If we cannot control bilirubin levels with the biliblanket, we might have to admit your baby to the Special Care Baby Unit (SCBU) for more intensive treatment (such as overhead phototherapy lamps). The SCBU is next door to the postnatal ward and we encourage you to be with your baby as much as possible while they are on the SCBU.

How long will the jaundice last?

The length of time babies remain jaundiced is different for each baby. Usually bilirubin levels increase over the first few days, then decrease slowly over the next 1-2 weeks.

When a baby is having phototherapy treatment, we do regular blood tests to check the bilirubin level, which needs to be below a certain level before deciding to stop phototherapy. The blood tests are done by taking a small sample of blood from a heel prick. It usually takes at least a couple of days for the bilirubin levels to reduce sufficiently to stop the phototherapy treatment.

Once the phototherapy has been stopped we will need to take another blood test, 8-12 hours later, to make sure the level is not rising again.

Does jaundice cause any long-term problems?

For most babies, jaundice does not cause any long-term problems. Very rarely, the amount of bilirubin in a baby’s blood is so high that it can cause problems such as hearing loss or cerebral palsy. We treat jaundice at the low levels we do, to give your baby a large safety margin to avoid these complications.
These complications are extremely rare and with the right treatment the small risk is reduced even more.

Leaflet number: 4475/VER2
Date published: December 2020
Review date: December 2023
© 2020 Guy’s and St Thomas’ NHS Foundation Trust
A list of sources is available on request


Printable PDF

Download Jaundice in newborn babies (PDF 322Kb)

Was this helpful?

If you have any comments about this information, we would be happy to hear from you. Fill in our simple online form or email:


Our information is changing

Find out how we are making our patient information more accessible and inclusive.

Evelina London Medicines Helpline

If you have any questions or concerns please contact

If you have any questions or concerns about your child’s medicines, please speak to the staff caring for them or contact our helpline.

Tel: 020 7188 3003 
(Monday to Friday, 10am-5pm)

Email: letstalkmedicines@

©  Guy's and St Thomas' NHS Foundation Trust.
King's Health Partners logo