Dad shared a photo of his newborn daughter online—and it helped save her life.

In newborns, it is usually caused by an increased amount of bilirubin in the blood.

Bilirubin is produced when red blood cells are broken down.

Everyone produces it.

Normally, the liver processes bilirubin so the body can eliminate it.

Newborn babies face a temporary challenge.

Their bodies produce relatively large amounts of bilirubin, while their immature livers may not yet remove it as efficiently as an older child or adult would.

As a result, bilirubin can build up.

That is why newborn jaundice is so common.

And in most babies, it is not dangerous.

Many Newborns Develop Some Degree of Jaundice

The appearance of mild jaundice during the first days of life is not unusual.

American Academy of Pediatrics materials note that more than half of newborns develop visible jaundice during the first week.

It often becomes most noticeable a few days after birth.

For many babies, bilirubin levels then fall naturally as the liver matures and feeding becomes established.

The yellow color gradually fades.

Most cases do not lead to complications.

But “common” does not mean “ignore it.”

The reason doctors monitor jaundice carefully is what can happen when bilirubin rises much higher than expected.

The Danger Comes From Very High Bilirubin Levels

Most neonatal jaundice is mild.

Rarely, however, bilirubin can rise to levels capable of affecting the nervous system.

Severe hyperbilirubinemia can lead to acute bilirubin encephalopathy.

If bilirubin-related brain injury becomes permanent, the condition is known as kernicterus.

Kernicterus can cause serious neurological problems, including movement disorders and hearing loss.

This is why pediatric guidelines place so much emphasis on identifying babies whose bilirubin is rising too high.

The goal is to intervene before neurological injury occurs.