Newborn jaundice: why it happens, when it clears and when it is dangerous

Updated August 15, 2026

Newborn jaundice is very common: the skin and the whites of the eyes take on a yellowish tint because of bilirubin, which the baby's liver cannot yet clear fast enough. In most cases this is physiological, harmless jaundice that clears on its own.

But sometimes jaundice is a sign of a problem and needs treatment. Below: why it happens, when it appears and clears, what helps, and the signs that call not for watching but for an urgent visit to a doctor.

Why jaundice happens

At birth a baby has many "extra" red blood cells that begin to break down, and their breakdown produces bilirubin — a yellow pigment. A newborn's immature liver clears it slowly, so bilirubin builds up and colours the skin. This is physiological jaundice — not a disease, but a feature of the first days of life.

A separate kind is breastfeeding jaundice in the first days: if the baby takes in little milk, bilirubin is cleared less well. The answer here is not to stop breastfeeding but to establish frequent feeds. Other, rarer causes (blood-group or Rhesus incompatibility, infections, liver disease) need their own investigation.

When it appears and when it clears

Physiological jaundice usually appears on day 2–3 of life, peaks around day 3–5, and gradually fades, clearing fully by 1–2 weeks (sometimes a little longer in breastfed babies). The skin yellows "top to bottom": first the face, then the chest and abdomen, and in severe cases the legs and palms.

The timing matters most: jaundice appearing in the first 24 hours of life, or lasting longer than 2–3 weeks, is not considered physiological and must be reviewed.

What helps

1. Frequent feeds. Feed on demand, 8–12 times a day. The more the baby feeds, the more actively bilirubin is cleared in the stool and urine. This is the main thing you can do at home.
2. Watch the nappies. Enough wet nappies and regular stools are an indirect sign that milk is sufficient and bilirubin is being cleared.
3. Monitoring and checks. With marked jaundice a doctor measures the bilirubin level (by blood or a skin device) and decides whether treatment is needed.
4. Phototherapy — as prescribed. With a high bilirubin the baby is placed under a special lamp: its light breaks down the pigment in the skin. It is a safe and standard treatment, but is used only when indicated.

What not to do

• Do not "sunbathe" by a window or in the sun. The "hold them by the window" advice does not work, and direct sun risks overheating and burns. What treats jaundice is medical phototherapy, not household light.
• Do not top up with water or glucose "to flush out the bilirubin". It does not speed clearance and can reduce milk intake — bilirubin is cleared with milk and stool, not with water.
• Do not stop breastfeeding on your own. In most cases the baby needs to breastfeed more often, not less. Make any change only on a doctor's advice.
• Do not judge jaundice "by eye" in poor light. How yellow the skin looks can be misleading; if in doubt, a doctor measures it.

How to watch at home

While jaundice clears, it matters that the baby feeds enough and stays alert. Logging feeds, the number of wet nappies and stools makes it easier to notice that milk is falling short or that the baby has become more listless and sleepy — which, together with the skin colour, is exactly what to show the doctor in time. A written picture over a few days is far clearer than trying to recall "how many times did they feed today".

Frequently asked questions

This article is for general information and does not replace medical advice. Only a doctor can assess the bilirubin level and the need for treatment. With early, deepening or prolonged jaundice, or lethargy or refusal to feed, seek medical help without delay.