Newborn Jaundice: What to Expect, How It is Checked, Treatment and When to Seek Help
You bring your baby home, stare at their tiny face for hours, and then you notice it: their skin looks a bit yellow. Maybe the whites of their eyes too. Your heart sinks.
Is this normal? Or is something wrong?
Newborn jaundice is one of those things almost every parent hears about but few really understand until they are in it. The good news: in most babies, newborn jaundice is normal and temporary. Still, there are times when it needs urgent attention.
This guide walks you through both sides - when to relax, and when to pick up the phone and call your GP or NHS 111 straight away.
What is newborn jaundice?
Jaundice is when a baby’s skin and the whites of their eyes look yellow. It happens when there is too much bilirubin in the blood.
Bilirubin is a yellowish substance produced when the body breaks down old red blood cells. Adults get rid of bilirubin through the liver, which processes it and sends it out in poo.
Newborns are a bit different:
- They have more red blood cells than adults
- Their red blood cells break down faster
- Their liver is still immature, so it is slower at processing bilirubin
If bilirubin builds up faster than the liver can clear it, it starts to show in the skin. That is neonatal jaundice or baby jaundice.
You might notice:
- Yellow skin, especially on the face, chest, and sometimes legs
- Yellow tint in the whites of the eyes
- The yellow colour appearing when you gently press a finger on the skin and then release
This is the classic newborn jaundice symptom that midwives, health visitors, and paediatricians look for.
How common is newborn jaundice?
Very common.
- Around 60% of full-term babies develop some jaundice in the first week
- Around 80% of preterm babies (born before 37 weeks) have jaundice
So if your baby has a yellowish tone, you are definitely not alone. Midwives and neonatal doctors in the UK see cases of jaundice in newborns every single day.
The question is not usually “Does my baby have jaundice?” but rather “What kind of jaundice is this, and is it safe?”
Physiological jaundice: the normal kind
The most common type is called physiological jaundice. That simply means it is part of the body’s normal adjustment after birth.
When does physiological jaundice appear?
In a healthy full-term baby, physiological jaundice:
- Usually starts after 24 hours of life, often around day 2 or 3
- Peaks around day 3 to 5
- Gradually fades and usually resolves by about 2 weeks of age
In premature babies it can last a bit longer, sometimes up to 3 weeks, because their liver is even more immature.
This timeline matters. Doctors pay a lot of attention to when the yellow colour starts and how long newborn jaundice lasts.
If your baby is otherwise well, feeding often, and the jaundice appeared on day 2 or 3 and is slowly improving, it is most likely physiological jaundice.
Breastfeeding jaundice vs breast milk jaundice
Here is where the terms get confusing for parents. You might hear about:
- Breastfeeding jaundice
- Breast milk jaundice
They sound similar, but they actually mean slightly different things.
Breastfeeding jaundice
This usually appears in the first week of life and is linked to not getting enough milk.
Common reasons:
- Baby is very sleepy and not waking to feed often
- Latch is not quite right, so baby is not transferring enough milk
- Milk supply is still coming in and baby is getting only small amounts of colostrum
- Feeds are short, infrequent, or baby is given lots of top ups early on and does not feed as much from the breast
When babies do not get enough milk:
- They poo less often
- They do not clear bilirubin as quickly
- Bilirubin builds up and jaundice gets more noticeable
This is what doctors often call breastfeeding jaundice.
Key point: The issue here is not that breastfeeding causes jaundice. It is that insufficient feeding slows down bilirubin removal.
What helps:
- Feed very frequently, at least 8 to 12 times in 24 hours
- Make sure the latch is deep and comfortable
- Wake a sleepy baby for feeds if needed
- Ask your midwife, health visitor, or a breastfeeding counsellor (for example from the National Childbirth Trust or La Leche League GB) to watch a full feed
- In some cases, your midwife or doctor may suggest expressing and offering extra breast milk, or occasionally short-term formula top ups, while protecting your milk supply
Often, once feeding improves, bilirubin levels in newborns start to fall and the yellow colour fades.
Breast milk jaundice
Breast milk jaundice is different.
- It usually appears after the first week, often around days 5 to 7
- Baby is otherwise well, alert, gaining weight, and feeding brilliantly
- Jaundice can sometimes last several weeks, even up to 12 weeks, although it usually gets lighter over time
Some substances in breast milk seem to slow the way the liver processes bilirubin in a small number of babies. This keeps levels a bit higher for longer.
Doctors often diagnose breast milk jaundice when:
- Baby had normal physiological jaundice that lasted a bit longer
- Baby is thriving, with no signs of illness
- Other causes of jaundice have been ruled out
Most UK paediatricians do not recommend stopping breastfeeding for this. Baby jaundice from breast milk alone is usually harmless, and breastfeeding has big long-term benefits.
If there is any doubt, your baby might have a bilirubin test and sometimes other blood tests, just to make sure nothing more serious is going on.
How is newborn jaundice checked and measured?
Midwives and doctors do not just rely on a quick glance.
They use a few different methods to assess neonatal jaundice.
1. Visual assessment
First, they will:
- Look at your baby in good natural light
- Check the colour of the face, chest, tummy, arms, and legs
- Look at the whites of the eyes
- Sometimes gently press on the skin to check the underlying colour
This visual check is helpful, but it is not perfect, especially in babies with darker skin tones. So if jaundice looks more than mild or baby is very young, they will often use a device or blood test.
2. Transcutaneous bilirubinometer
You might see a little handheld device placed on your baby’s forehead or chest. This is a transcutaneous bilirubinometer.
- It shines a light into the skin
- Measures how much light is absorbed
- Estimates the bilirubin level in the newborn
It is quick, painless, and done right at the cot side.
If the reading is high, or baby is very small or premature, your baby will usually have a bilirubin blood test to confirm the exact level.
3. Blood test (serum bilirubin)
For this test, a small blood sample is taken from your baby’s heel or a vein. The lab measures the exact:
- Total serum bilirubin level
- Sometimes also the types of bilirubin (conjugated and unconjugated)
Hospitals use specific charts (for example, NICE guidelines in the UK) that show:
- What bilirubin level is acceptable for your baby’s age in hours
- When treatment such as phototherapy for newborn jaundice is needed
- When closer monitoring or transfer to hospital is required
You might hear staff talking about “the line” on the jaundice chart. They are checking if your baby’s bilirubin level is below or above the treatment threshold.
Newborn jaundice treatment: what usually happens
Treatment depends on:
- How high the bilirubin is
- How fast it is rising
- How old your baby is
- Whether your baby was born at term or prematurely
- Whether there are other health issues
Frequent feeding
For mild baby jaundice, the main newborn jaundice treatment is very simple:
- Feed often - at least 8 to 12 times in 24 hours
- Make sure baby is swallowing well and seems satisfied
- Avoid long gaps between feeds in the early days
Good feeding leads to more poo. More poo means more bilirubin leaves the body.
If you are breastfeeding, you might be offered help with positioning and latch. If you are formula feeding, you will be encouraged to keep feeds regular and watch that baby is taking adequate amounts.
Phototherapy
If bilirubin levels are higher, your baby might need phototherapy for newborn jaundice.
Phototherapy uses a special kind of light to change bilirubin in the skin into a form the body can get rid of more easily.
What it looks like in hospital:
- Baby is placed under blue lights or on a special phototherapy blanket
- Only a nappy is left on, to expose as much skin as possible
- Babies wear little eye shields to protect their eyes
- Feeds continue as usual, sometimes more frequently
- Blood tests are done regularly to see if bilirubin levels in the newborn are dropping
Phototherapy is safe and very effective. Many babies only need it for 1 to 2 days.
Once bilirubin has come down below the treatment threshold, the lights are stopped. There can be a small “rebound” rise, so sometimes another blood test is done a bit later to make sure the level stays low enough.
Very severe jaundice
In rare cases, if bilirubin levels become dangerously high or are rising very quickly, more intensive treatment may be needed in a neonatal unit. This could include:
- Intensive phototherapy with multiple light sources
- In extreme cases, an exchange transfusion, where some of the baby’s blood is replaced with donor blood
This is uncommon, particularly when jaundice is picked up early. The reason doctors take high jaundice levels seriously is that very high bilirubin can affect the brain and cause a condition called kernicterus. Luckily, this is rare in the UK and early bilirubin tests in newborns help to prevent it.
When jaundice is not normal: warning signs to watch for
Most newborn jaundice is harmless. Still, there are red flags that suggest pathological jaundice - jaundice caused by an underlying problem rather than just normal adjustment.
Here are the key warning signs.
1. Jaundice appearing within the first 24 hours
If your baby looks noticeably yellow in the first day of life, that is not considered normal physiological jaundice.
Possible causes include:
- Blood group incompatibility between mother and baby (like Rhesus or ABO problems)
- Infection
- Rare blood disorders
This type of jaundice needs urgent assessment in hospital. Call your midwife, GP or NHS 111 straight away, or go to A&E if you are worried and cannot get rapid advice.
2. Very high or rapidly rising bilirubin levels
If tests show that bilirubin levels in your newborn are:
- Very high for their age
- Climbing quickly between tests
Doctors will treat more aggressively and look for causes, such as:
- Haemolytic disease (baby’s red blood cells breaking down too quickly)
- Severe bruising from birth
- G6PD deficiency
- Infection
This is not something you can see yourself at home, but you might be told by staff that treatment is urgent.
3. Jaundice lasting beyond 2 weeks
For most full-term babies, physiological jaundice:
- Peaks around day 3 to 5
- Is much lighter by 10 days
- Usually gone by 2 weeks
If your newborn jaundice lasts longer than 2 weeks, especially if it is still quite noticeable, your GP or paediatrician will want to investigate.
They may check for:
- Breast milk jaundice
- Infection
- Liver or bile duct problems, such as biliary atresia
- Metabolic or endocrine disorders (such as hypothyroidism)
Preterm babies can have jaundice for a bit longer, but it still needs a proper check if it seems persistent.
4. Dark urine and pale stools
This is a big one and easy for parents to spot.
Normal newborn poo:
- Breastfed babies - mustard yellow, seedy, can be quite runny
- Formula-fed babies - pale yellow to tan, thicker
Normal newborn urine:
- Light yellow
- In the first few days you might see a faint orange “brick dust” stain from urates, which usually disappears
Warning signs:
- Very dark urine that looks like strong tea
- Pale, chalky, or almost white stools
These can suggest a problem with bile flow from the liver, such as biliary atresia. This needs urgent specialist assessment, because early treatment can make a real difference.
5. Lethargy or poor feeding
If jaundice is accompanied by:
- Baby being very sleepy and hard to wake
- Weak or slow feeding
- Less than 6 wet nappies a day after day 4
- Fewer dirty nappies than expected
- Floppy muscle tone or baby feeling “not quite right”
Then it is time to seek help quickly. Severe jaundice or infection can both cause this picture.
When to call the doctor immediately
Contact your GP, midwife, health visitor or NHS 111 right away or go to A&E if:
- Your baby looks yellow in the first 24 hours after birth
- The yellow colour seems to be getting rapidly worse, spreading from face to abdomen and legs
- Your baby is very sleepy, difficult to wake, or not interested in feeds
- Feeds are poor, baby is barely swallowing, or having fewer wet nappies
- You notice dark urine and very pale or white-looking stools
- Your baby has a high temperature, seems unwell, or you simply feel something is wrong
Trust your instincts. Parents often spot changes before anyone else.
For less urgent concerns, such as mild jaundice that seems to be lingering around the 2 week mark but baby is otherwise well, book an appointment with your GP or paediatrician. They can arrange a bilirubin test in your newborn and any other checks needed.
So, is newborn jaundice normal?
In many babies, yes.
- Physiological jaundice in the newborn is a normal phase as their liver matures
- Breastfeeding jaundice usually improves once feeding is well established
- Breast milk jaundice can last longer but is usually harmless in an otherwise thriving baby
Normal patterns:
- Appears after 24 hours, usually on day 2 or 3
- Peaks around days 3 to 5
- Gradually fades, often gone by 2 weeks in full-term babies
- Baby is alert, waking for feeds, with plenty of wet and dirty nappies
Not-so-normal patterns:
- Starts in the first 24 hours
- Very strong yellow colour or rapid worsening
- Lasts beyond 2 weeks with no improvement
- Accompanied by dark urine, pale stools, or a very sleepy, poorly feeding baby
If you are ever unsure, ask. Show your midwife or health visitor your baby in good light. Describe nappies in detail. Ask if a bilirubin test for your newborn is needed.
You are not being over-anxious. You are doing exactly what a good parent does: paying attention and asking questions.
Most jaundiced babies are back to their normal colour in a matter of days. In the meantime, keep offering those frequent feeds, enjoy those sleepy cuddles under the blanket (not the blue lights, ideally), and remember that a lot of this early worry is part of getting to know your baby.
If something is not right, early action really helps. If everything is normal, you get reassurance and can relax a little.
Either way, you and your baby do not have to figure out newborn jaundice on your own. Your NHS team is there to help you through it.
We as the developers of the Erby app disclaim any liability for any decisions you make based on this information, which is provided for general informational purposes only and is not a substitute for personal medical advice.
