Jaundice makes a newborn's skin and the whites of their eyes look yellow. It is common: Australia's Pregnancy, Birth and Baby service says mild jaundice affects about 1 in every 2 full-term newborns. It is usually most noticeable from day 2 or 3 and fades within about 2 weeks. Most jaundice is harmless, but a few patterns need fast action: jaundice in the first 24 hours, a jaundiced baby who is very sleepy or not feeding, pale poo or dark urine, and jaundice that hasn't gone after 2 weeks.
What is newborn jaundice and why is it so common?
Jaundice comes from bilirubin, a yellow substance made when old red blood cells are broken down. The liver normally clears it into the poo. A newborn's liver is still maturing, so bilirubin can build up for a while. The Australian Pregnancy, Birth and Baby page says that by about 2 weeks of age the liver is better at removing it, and this everyday "physiological" jaundice settles on its own.
Some babies are more likely to have jaundice that needs treatment. The UK guideline from NICE, CG98 on jaundice in newborn babies, lists:
- birth before 38 weeks
- an older brother or sister who needed phototherapy for jaundice
- a mother who plans to breastfeed exclusively (the AAP links this to babies not yet getting enough milk while feeding gets established)
- jaundice seen in the first 24 hours of life.
Less common causes include not getting enough milk, infection, blood group differences between mother and baby, an underactive thyroid, and rare liver conditions such as biliary atresia, according to Australia's Pregnancy, Birth and Baby.
When does jaundice start, and how long does it last?
| Pattern | Typical timing | What it means |
|---|---|---|
| Usual newborn jaundice | Shows around day 2 to 3, fades in 1 to 2 weeks | Common and usually harmless; still needs checking |
| Early jaundice | Seen in the first 24 hours | Urgent: can signal a blood or other problem |
| Breast milk jaundice | Can start around day 5 to 7 and last weeks | Usually harmless, but only once other causes are ruled out |
| Prolonged jaundice | Past 14 days (21 if born before 37 weeks) | Needs medical review and tests |
The NHS page on newborn jaundice says yellowing is usually most noticeable around day 3 and usually takes around 2 weeks to go. The breast milk jaundice timings come from the Royal Children's Hospital Melbourne guideline on jaundice in early infancy in Australia, which says it typically starts 5 to 7 days after birth, peaks at 2 to 3 weeks and can last up to 12 weeks in healthy, thriving breastfed babies.
How do I check my baby for jaundice?
NICE says parents, carers and health professionals should all look for jaundice, especially in the first 72 hours. To check:
- Undress your baby in bright light, ideally daylight near a window.
- Look at the whites of the eyes. Yellow here is often easier to see than on skin.
- Look at the gums, and under the tongue or inside the cheeks, as the NHS suggests.
- Press gently on the tip of the nose or the forehead for a moment. In a jaundiced baby, the pressed (blanched) skin looks yellowish rather than pale.
- Notice where the yellow reaches. Jaundice usually starts on the face and head and spreads down the body as bilirubin rises.
- Check nappies for dark yellow or brown urine and for pale, chalky or white poo.
On black or brown skin, yellowing of the skin is harder to see, as both the NHS and NICE point out, so the eyes, gums and inside of the mouth matter more. Looking can tell you jaundice is there, but not how high the level is. NICE says not to rely on looking alone, so a jaundiced baby needs a bilirubin test.
When is newborn jaundice urgent?
Use these tiers, which follow the NHS advice. If you are unsure which tier you are in, choose the more urgent one.
Australia's Pregnancy, Birth and Baby lists jaundice in the first 48 hours as a reason to see a doctor; for the first 24 hours we follow the NHS's stricter emergency advice above.
Contact your midwife, GP or a health advice line (Pregnancy, Birth and Baby on 1800 882 436 in Australia, NHS 111 in the UK, your pediatrician's after-hours line in the US) urgently, the same day, if:
- your baby is over 24 hours old and you think they have jaundice
- jaundice has been diagnosed and is not improving, or is getting worse
- their urine is dark yellow or brown, or their poo is pale, creamy, chalky or white (keep the nappy or a photo to show the clinician)
- the jaundice becomes more noticeable after the first week, or your baby is feeding poorly or not gaining weight, which Australia's Pregnancy, Birth and Baby lists as reasons to see a doctor.
Any fever in a baby under 3 months needs urgent medical advice, whether or not they are jaundiced. See fever in babies.
Call your GP or child-health nurse today to arrange a check (don't wait for a routine visit) if:
- jaundice is still visible after 14 days in a baby born at 37 weeks or later, or after 21 days in a baby born before 37 weeks (this is the NICE definition of prolonged jaundice).
Pale poo needs urgent evaluation at any age, because conditions such as biliary atresia need early treatment. Australia's Royal Children's Hospital guideline says this, and our guide to baby poo has more on colours.
How is jaundice tested and treated?
Tests
A bilirubin level is measured with a light meter held against the skin (a transcutaneous bilirubinometer) or with a heel-prick blood test. NICE recommends the skin meter for babies born at 35 weeks or later who are over 24 hours old, and a blood test in the first 24 hours of life or for babies born before 35 weeks. The result is compared with a chart for your baby's age in hours. Further blood or urine tests, or a liver ultrasound, may be needed if something other than everyday jaundice is suspected.
In the US, the AAP's HealthyChildren.org page on jaundice says most babies who go home before 48 hours old should be seen by a health professional within 2 days.
Treatment
- Mild jaundice: often needs no treatment beyond frequent feeds and monitoring.
- Phototherapy: your baby lies undressed under a special blue light, or on a light blanket, with their eyes protected. The light helps the body break down bilirubin. The NHS says most babies need about 48 hours. The Australian Pregnancy, Birth and Baby page says side effects are usually minor, such as a mild rash or runny poo for a few days. NICE encourages short breaks of up to 30 minutes for feeds, nappy changes and cuddles.
- Severe jaundice: very high levels may need an exchange blood transfusion or other hospital treatment. The Australian Pregnancy, Birth and Baby page says this is very uncommon. Very high bilirubin can rarely cause brain damage and hearing loss, which is why levels are monitored closely.
Sunlight is not a treatment. NICE, the AAP and Australia's Royal Children's Hospital all advise against using it. NICE also lists remedies that should not be used, including homeopathy, acupuncture and traditional Chinese medicine.
Can I keep breastfeeding if my baby has jaundice?
Usually, yes. NICE says to reassure parents that breastfeeding can usually continue, and Australia's Royal Children's Hospital guideline says not to stop breastfeeding for breast milk jaundice.
What helps:
- Feed often. The NHS suggests about 8 to 12 feeds a day, and NICE encourages waking a sleepy baby for feeds if needed. See is my baby getting enough milk?.
- Get early help with latch and supply. The AAP notes jaundice is more common in breastfed babies who aren't yet getting enough milk. Ask your midwife, child-health nurse or a breastfeeding helpline (the Australian Breastfeeding Association on 1800 686 268 in Australia, the National Breastfeeding Helpline on 0300 100 0212 in the UK), and see the first week of breastfeeding.
- Don't swap milk for water. NICE says breastfed babies having phototherapy should not be given extra fluids, and that your expressed milk is the first choice if an extra feed is needed. Some babies are prescribed formula top-ups for a time; follow your care team's plan.
For formula-fed babies, the AAP says most jaundice is gone by 2 weeks. Keep to your baby's usual feeds and watch their wet nappies.
What happens if jaundice lasts longer than 2 weeks?
Jaundice past 2 weeks can be harmless breast milk jaundice, but Australia's Royal Children's Hospital guideline calls that a diagnosis of exclusion: other causes, such as liver, thyroid, blood or infection problems, have to be ruled out first. That is why prolonged jaundice is always checked. NICE advises looking for pale chalky poo and dark urine that stains the nappy, and doing blood tests including a conjugated bilirubin level. It also says to make sure routine newborn screening, which includes a thyroid test, has been done.
Sources draw the line slightly differently:
- NICE (UK) and the Royal Children's Hospital (Australia): jaundice lasting more than 14 days (2 weeks) in a baby born at term needs review; NICE uses 21 days for babies born before 37 weeks.
- The AAP (US): call the doctor if jaundice lasts more than 2 weeks in a formula-fed baby or more than 4 weeks in a mainly breastfed baby.
If your baby was born at term and is still yellow at 2 weeks, call your GP or child-health nurse that day to arrange a check, and ask to be seen the same day if their poo is pale or their wee is dark.
What should I keep track of while my baby is jaundiced?
Jot down feed times, wet and dirty nappies, and the colour of the poo and urine, plus whether the yellow is spreading or fading. A dated photo of a pale nappy is useful to show a clinician. If phototherapy was needed, note the dates so your GP or child-health nurse has them at later checks.
