Newborn jaundice, calmly explained

Most newborns go a little yellow in the first week, and for most of them it is harmless and short-lived. It is also one of the few common newborn things worth understanding well, because the rare severe version is almost entirely preventable when it is caught early. Here are the calm facts, and the clear line for when to call.

1. Why it happens

Your baby was born with extra red blood cells, and as those break down they release a yellow pigment called bilirubin. A newborn liver takes a few days to get good at clearing it, so a little builds up and tints the skin, starting with the face. This is the ordinary, expected kind, and it fades as the liver catches up.

2. The timeline that matters

Jaundice usually appears in the first few days, and bilirubin tends to peak around days 3 to 5. That timing is exactly why your pediatrician wants to see your baby in that window, often within a day or two of leaving the hospital. In formula-fed babies most jaundice is gone by 2 weeks, and in breastfed babies it commonly lasts a month or occasionally longer. Let your pediatrician know if your baby is still yellow after 2 weeks. Two timings always need action. Yellow in the first 24 hours needs emergency care now while your baby is still under a day old, and a visit right away after that. Jaundice that starts or is still getting deeper after the first week needs a call to the office.

3. Reading it head to toe

Bilirubin colors the body from the top down as it rises: face first, then chest and belly, then arms and legs. Yellow only on the face is usually the mild end. Once the yellow reaches the belly or arms, or the whites of the eyes turn yellow, there is more bilirubin and it is worth a same-day call. Yellow that reaches the legs, or skin that looks deep yellow or orange, needs a call right away. Look in daylight or bright white light, such as fluorescent light, and press gently to see the color as the skin blanches. On darker skin the yellow is harder to see, so also check the whites of the eyes, the gums, and inside the lips, and if you are in any doubt, ask for a bilirubin test. Home checks are only a rough guide, the real number is a two-minute test at the office, so never talk yourself out of calling because the skin “does not look that bad.”

4. The treatment is routine

Many babies need nothing but time and frequent feeding, which moves bilirubin out through their stools (this is part of why wet and dirty diaper counts matter in the first week). When a level is high, the standard fix is phototherapy: the baby rests under special blue lights that break bilirubin down, sometimes for a night in the hospital. It is common, safe, and effective.

When to call, and how fast

Call 911 or go to the ER now if your baby:

Cries inconsolably or with a high pitch.
Is arched like a bow, with the head or neck and the heels bent backward.
Has a stiff, limp, or floppy body, jerking or twitching movements, or strange eye movements.
Is hard to wake, cannot be woken, or is sleepier than normal.
Is feeding poorly (a weak suck, or will not finish feeds), or is not feeding.
Has trouble breathing: grunting, the belly sucking in under the ribs, or breathing very fast.
Has had no wet diapers, or no pee in more than 8 hours.
Has a temperature of 100.4°F (38°C) or higher, or 96.8°F (36°C) or lower.
Is less than 24 hours old and looks yellow.

Get your baby seen right away, not later today, if your baby:

Turned yellow in the first 24 hours of life and is older now.
Looks deep yellow or orange, the yellow has reached the legs, or it looks worse than when a doctor last checked.
Has pale, chalky, white, or gray poop, or dark yellow or brown pee. Keep the diaper to show the doctor.

Call the doctor the same day if your baby:

Has yellow that has spread to the belly or arms, or yellow in the whites of the eyes.
Has too few wet or dirty diapers.
Is very fussy.

Call the office if your baby:

Is still yellow after 2 weeks. In breastfed babies it commonly lasts longer, but let the office know.
Turns yellow, turns yellow again, or gets deeper yellow after the first week.

None of this is meant to frighten you. Ordinary newborn jaundice is harmless and passes. The reason to know the red flags is simple: catching the rare high level early is what keeps it harmless. Keep the early appointment, and when in doubt, call, that is always allowed.

Frequently asked questions

Why do so many newborns turn yellow?

Jaundice is the yellowing of the skin and the whites of the eyes, and it is extremely common in the first days of life. A newborn is breaking down the extra red blood cells they were born with, which makes a pigment called bilirubin, and their brand-new liver needs a few days to get efficient at clearing it. While the liver catches up, bilirubin builds up a little and tints the skin. In most babies it is mild and passes on its own.

When does jaundice appear and when does it go away?

It usually shows up in the first few days after birth. Bilirubin tends to peak when a baby is about 3 to 5 days old, which is exactly why that early pediatric visit matters so much. In formula-fed babies most jaundice is gone by 2 weeks, and in breastfed babies it commonly lasts a month or occasionally longer, so let your pediatrician know if your baby is still yellow after 2 weeks. A baby who is less than 24 hours old and looks yellow needs emergency care now: call 911 or go to the ER. If the yellow began in that first day and your baby is older now, get them seen right away. Yellow that starts, comes back, or keeps getting deeper after the first week needs a call to the office. And at any age, a yellow baby with pale, chalky, white, or gray poop, or dark yellow or brown pee, needs a call right away.

How can I tell how bad it is at home?

Jaundice starts at the head and works downward as bilirubin rises: face first, then chest and belly, then arms and legs. Yellow only on the face is generally the mild end. Yellow that has reached the belly or arms, or yellow in the whites of the eyes, is a reason to call the same day, and yellow that has reached the legs or looks deep yellow or orange needs a call right away. Check in daylight or bright white light, such as fluorescent light, and press gently on the skin to see the color as it blanches. On darker skin the yellow is harder to see, so also look at the whites of the eyes, the gums, and inside the lips. Home checks are a rough guide only, the actual level is a quick test at the office, so if you are in any doubt, ask for one.

What is the treatment?

Many babies need nothing but time and good feeding, frequent feeds help move bilirubin out through their stools. When a level is high, the standard treatment is phototherapy: the baby rests under special blue lights that help break bilirubin down, sometimes overnight in the hospital. It is routine and effective. Feeding well and enough wet and dirty diapers are part of the picture, so keeping an eye on both matters.

Why is it so important to catch high jaundice?

Because in the rare cases where bilirubin climbs very high and is missed, it can harm the brain (a condition called kernicterus). That outcome is almost entirely preventable with the normal system of checks, which is the whole reason for the 3-to-5-day visit and the warning signs on this page. The message is not to panic, ordinary jaundice is harmless, the message is to keep the appointments and act on a red flag as fast as that list says, which for some signs means calling 911.

Sources

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Last updated September 2026. Next review December 2026. How we write these: built from current published guidance from the AAP, CDC, FDA/EPA, NIAID, WHO, and other pediatric and public-health authorities, with sources cited on the page. See our editorial and medical policy for how we research, source, and update these, and how we double-check the food advice.

This is general information, not medical advice, and is not individualized for your baby. Always talk to your pediatrician about your baby's diet, introducing allergens, and any reaction. In an emergency, contact emergency services.

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