When to worry about newborn jaundice, and why sunlight is not the answer

Mild yellow skin in the first week is common and usually harmless. It needs a doctor the same day if it starts in the first 24 hours, if the palms or soles turn yellow, if the baby is sleepy or feeding poorly, or if it lasts beyond 2 weeks. Sunlight on the balcony is not a safe treatment.

Why do newborn babies get jaundice?

Jaundice is a yellow colour of the skin and eyes caused by bilirubin, a pigment made when red blood cells break down. Newborns make a lot of it and clear it slowly.

Bilirubin travels in the blood to the liver. The liver changes it into a form that can leave the body in stool.¹ In the first days, several things add up:

• Babies are born with many red cells that they no longer need once they breathe air
• Newborn red cells live a shorter life, so more break down each day
• The newborn liver is slow to process bilirubin for the first few days
• Some bilirubin is reabsorbed from the gut if feeding and stooling are slow

Is newborn jaundice normal?

Yes, most of the time. A large share of term and preterm babies develop some jaundice in the first week.¹ In most healthy term babies it is "physiological", meaning it comes from normal newborn changes.¹

Physiological jaundice usually appears after the first day, is mild, and fades on its own. The key is not whether a baby is yellow, but how high the bilirubin is for the baby's age in hours, and whether there are risk factors. That is why we measure it rather than guess.

Is jaundice in the first 24 hours dangerous?

Yes, it needs a check the same day. WHO lists any jaundice in the first 24 hours after birth as a danger sign.²

Early jaundice often means red cells are breaking down too fast. This can happen when the mother's and baby's blood groups do not match (Rh or ABO incompatibility), or with G6PD deficiency. In these babies, bilirubin can rise quickly. A simple blood test tells us where things stand, and treatment started early works well.

How can I check my baby for jaundice at home?

Look at your baby in daylight near a window. Gently press the skin of the nose or chest for a second and see if it looks yellow as it blanches. The whites of the eyes and the gums are also good places to look.

But do not try to judge the level by eye. In one study, how far down the body the yellow had spread matched the real bilirubin level only moderately, and worse in babies born before 38 weeks.³ The useful part: a baby with no visible jaundice at all was very unlikely to develop a high level.³ If you see any yellow, especially on day 2 or 3, ask for a measurement.

How do doctors measure bilirubin in a newborn?

There are two ways: a light meter on the skin, and a blood test. The skin meter, called a transcutaneous bilirubinometer, is quick and painless.

A Cochrane review found that skin meters are good at ruling out high bilirubin.⁴ When the skin reading is high, a blood test is needed to confirm it.⁴ Most Indian hospitals now use both: the meter for screening, and blood for decisions about treatment.

Should every newborn have a bilirubin check before going home?

Yes. WHO recommends checking all babies with a skin bilirubin meter before discharge.² The 2022 American Academy of Pediatrics guideline advises measuring bilirubin between 24 and 48 hours after birth or before discharge.^5,6

A reading plotted against the baby's age in hours shows which babies are likely to develop high levels later.⁷ In the classic study, babies whose level was in the low-risk zone before discharge did not go on to develop high levels.⁷ This lets us plan who needs a recheck and when. If you leave hospital early, ask when the next bilirubin check should be.

What bilirubin level needs phototherapy?

There is no single number for all babies. The treatment level depends on the baby's age in hours, how many weeks pregnant the mother was at birth, and whether there are risk factors.^5,6

The 2022 American Academy of Pediatrics guideline uses charts based on gestational age and the baby's age in hours.^5,6 So a level that is fine at 4 days old may need treatment at 30 hours old. Babies with risk factors for brain injury from bilirubin have lower treatment thresholds.^5,6 Babies born before 35 weeks have their own, lower charts. Your doctor will plot your baby's value on the right chart.

What makes jaundice more dangerous for a baby?

Some babies are more at risk of brain injury from bilirubin. The American Academy of Pediatrics lists these risk factors:^5,6

• Birth before 38 weeks
• Fast breakdown of red cells, for example from blood group mismatch or G6PD deficiency
• Low albumin (a blood protein that carries bilirubin) in the blood
• Infection (sepsis) or suspected infection
• Being seriously unwell in the past 24 hours

If your baby has any of these, the team will treat at a lower bilirubin level. Tell your doctor about older siblings who needed phototherapy too.

What is G6PD deficiency and why does it matter for jaundice?

G6PD is an enzyme that protects red blood cells. Babies with an inherited lack of it can develop sudden, severe jaundice.⁸

G6PD deficiency is common in South Asia, with estimates of about 4 to 15 percent in different regions.⁸ In a newborn screening study from Eastern India, about 3 percent of babies had it.⁹ It is more common in boys.⁹ If anyone in your family has G6PD deficiency, or a baby in the family needed an exchange transfusion, tell your baby's doctor before discharge.

How does phototherapy work and is it safe?

Phototherapy is a simple and effective way to bring bilirubin down.¹ Used properly, it lowers bilirubin safely.¹⁰

It uses blue-green light matched to the colour that bilirubin absorbs.¹⁰ The light changes bilirubin in the skin so the body can get rid of it more easily. With effective lights, bilirubin usually starts to fall within 4 to 6 hours.¹⁰

Your baby lies under the lights in only a nappy, with the eyes covered. Most babies need it for a day or two. We check bilirubin during treatment and stop once it falls to a safe range. If levels are very high, more lights are added. A few babies need an exchange transfusion (replacing the baby's blood slowly), but this is rare when jaundice is caught in time.

Can I breastfeed my baby during phototherapy?

Yes. In almost all cases you can and should keep breastfeeding during phototherapy.

In Dr Dutta's unit, babies come out of the lights for short feeds unless the level is very high. In that case, the mother may feed with the baby still under the lights, or give expressed milk. Good feeding helps the baby pass stool, and stool carries bilirubin out of the body. Stopping breastfeeding is very rarely needed, and if someone suggests it, Dr Dutta would ask for a clear reason.

Can poor feeding make jaundice worse?

Yes. When a baby does not get enough milk in the first days, bilirubin tends to rise. This is often called breastfeeding jaundice, though the real problem is low intake, not breast milk.

In an Indian study of breastfed babies admitted with dehydration, over half were also jaundiced.¹¹ Those babies had fed less often and had lost much more weight than healthy babies.¹¹ The answer is more effective breastfeeding, not stopping it. Watch the nappy count, and get a weight check on day 3 to 5.

Can sunlight cure newborn jaundice?

No. Putting a baby in the sun at home is not a safe or reliable treatment for jaundice.

A Cochrane review found only very low-certainty evidence for plain sunlight, with no safety data for that use.¹² In the trials of filtered sunlight, overheating was clearly more common than with standard lights.¹² Here is why Dr Dutta always says no to the balcony:

• You cannot measure the dose. Cloud, season, glass and time of day all change it.
• The baby must be undressed, and newborn skin burns easily.
• In a Kolkata summer, overheating and dehydration are real risks. In winter, the baby gets cold.
• Families "treating" at home often come in late, when the level is already high.

What about filtered sunlight treatment I have read about?

That is a research treatment, not a home remedy. In a Nigerian hospital trial, babies were treated under special canopies that filtered out harmful rays.¹³

It worked about as well as standard lights in that trial.¹³ But even there, more babies had temperatures over 38 degrees C under filtered sunlight (5 percent compared with 1 percent).¹³ This was a controlled study in a hospital. It is a very different thing from a baby on a balcony.

Why is my baby still yellow at 2 weeks?

Jaundice that persists needs a blood test for conjugated bilirubin.¹

Prolonged jaundice can be a sign of a bile flow problem in the liver.⁶ In Dr Dutta's practice, any term baby still yellow at 2 weeks has this test. Often the cause is harmless, but it can pick up liver problems early.

The most important one to find is biliary atresia, a rare blockage of the bile ducts. Look at the stool colour. Pale, chalky, white or clay-coloured stools, or dark urine that stains the nappy, need urgent review. Surgery called the Kasai operation works better the younger the baby is.¹⁴ In a large French study, results got worse with every extra few weeks of age, and the authors argued for surgery before 46 days.¹⁴

What is kernicterus?

Kernicterus is permanent brain damage from very high bilirubin. It can cause cerebral palsy, hearing loss and problems with eye movements. It is almost always preventable with timely checks and treatment.

In India, deaths linked to extreme jaundice fell by about 60 percent between 1990 and 2019, but still numbered almost 20,000 in 2019.¹⁵ Early warning signs are a very sleepy baby who feeds poorly and is floppy. Later signs include a high-pitched cry, arching of the neck and back, fever and fits. These need emergency care.

When should I take my jaundiced baby to hospital?

Go to a hospital with a neonatal unit the same day if your baby:

• Turns yellow in the first 24 hours of life²
• Has yellow palms or soles at any age²
• Is very sleepy, hard to wake, or not feeding well
• Has a high-pitched cry, arches backwards, or seems stiff or floppy
• Is still yellow after 2 weeks, or has pale stools or dark urine at any age

If you were sent home and told to come back for a bilirubin check, please go. That follow-up visit is one of the most important appointments of the newborn period.