Newborn Jaundice: What It Is, Why It Happens, and When It's Dangerous

What is newborn jaundice?

Newborn jaundice is a yellowish change in color seen in a baby's skin and the whites of the eyes. It develops when a yellow substance called bilirubin builds up in the blood. In the great majority of newborns, seeing some degree of jaundice — especially in the first few days — is extremely common, and most of the time there is no need for alarm.

Babies come into the world with a high number of red blood cells, and as these cells are renewed, bilirubin is released. Because a newborn's liver has not yet fully matured, clearing this substance from the body is slow in the first few days. For this reason, in most babies jaundice begins on the 2nd–3rd day after birth, usually starting on the face and spreading down toward the body.

Most jaundice is harmless and subsides on its own; this is called 'physiological jaundice.' Even so, because bilirubin levels can rise in some cases, it needs to be monitored. In this article we explain why jaundice happens, which picture is normal and which calls for attention, what phototherapy means, and when you should see a doctor without losing any time. Remember: only your doctor can assess the degree of jaundice and its treatment.

Why does jaundice happen?

The most common cause of newborn jaundice is that the baby's liver has not yet reached the maturity needed to process bilirubin. This picture usually resolves on its own. However, there can be other causes underlying jaundice, and telling them apart is the doctor's job.

In the first few days, a baby not feeding often enough, a blood-type incompatibility between mother and baby, or bruising that formed during birth can make jaundice more pronounced. In babies born early, jaundice can also be more frequent and last longer. For this reason, rather than trying to interpret the cause, it is important not to miss check-ups.

• ✓ The liver not yet being mature (the most common cause)
• ✓ Not feeding often enough in the first days, and low fluid intake
• ✓ Blood-type (Rh/ABO) incompatibility between mother and baby
• ✓ Early (premature) birth
• ✓ Extensive bruising or bleeding that occurred during birth
• ✓ Infection or certain inherited conditions (rarer causes the doctor investigates)

Physiological jaundice or dangerous jaundice?

Physiological jaundice usually begins 2–3 days after birth, becomes most pronounced around the 4th–5th day, and most often subsides on its own within the first week or two. During this time the baby feeds well, is alert, and is on track with weight gain. With such a picture, there is no need to panic — keeping up with doctor check-ups is enough.

By contrast, jaundice that appears within the first 24 hours, darkens very quickly, spreads all the way to the palms and soles, or lasts longer than two weeks requires closer evaluation. Estimating the degree of the color by eye is not reliable, so the decision always belongs to the doctor.

• ✓ Usually benign: jaundice that starts on the 2nd–3rd day and stays mild while the baby feeds well
• ✓ Warning: jaundice that begins in the first 24 hours after birth
• ✓ Warning: jaundice darkening rapidly, or spreading to the legs, palms, and soles
• ✓ Warning: jaundice that does not go away even after two weeks
• ✓ Warning: dark urine and pale/light-colored stools
• ✓ The baby being excessively sleepy, hard to wake, or refusing to feed

What does phototherapy mean, and what should a gentle approach at home look like?

Phototherapy — that is, 'light therapy' — is a method carried out in the hospital when bilirubin levels rise above a certain limit. The baby is kept under a special blue light; this light converts bilirubin into a form the body can eliminate more easily. Only the doctor decides whether phototherapy is needed, based on the baby's blood levels and age.

The best support for jaundice at home is feeding the baby frequently and sufficiently, because as feeding increases, bilirubin is cleared more quickly through stool and urine. The widely shared folk advice to 'lay the baby in the sun or by a window' is not a safe treatment: direct sun can easily burn a baby's skin and overheat them. So do not use the sun as a treatment; instead, focus on feeding and keep up with doctor check-ups.

• ✓ Feed the baby often throughout the day, at the intervals your doctor recommends
• ✓ Track the wet diaper count and bowel movements; a decrease can indicate inadequate fluid intake
• ✓ Phototherapy is a hospital treatment; do not try to mimic it at home with a lamp or blue light
• ✓ Do not try to 'clear the jaundice' by laying the baby in direct sun or by a window
• ✓ Keep the room temperature balanced — neither overheat nor chill the baby
• ✓ Rather than interpreting the color and the picture yourself, do not miss doctor check-ups

When should you see a doctor?

Although most jaundice is benign, some signs call for evaluation without losing any time. If any of the situations below is present, take your baby to a healthcare facility right away; it being night or the weekend is not a reason to wait. Whenever you are in doubt, be sure to consult your doctor.

• ✓ If jaundice began within the first 24 hours after birth
• ✓ If the baby is so weak and floppy that you can barely wake them, or, on the contrary, is constantly fretful and crying in a high-pitched voice
• ✓ If the baby refuses to feed, will not take the breast or bottle, or is sucking noticeably less
• ✓ If there is fever, fast or labored breathing, bluish skin, or repeated vomiting
• ✓ If the jaundice is darkening, spreading to the palms and soles, or lasting longer than two weeks
• ✓ If the urine is dark, the stools are pale/light-colored, or the wet diaper count has dropped noticeably

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