Under these normal circumstances, mild jaundice typically disappears on its own, leaving no lasting effects. However, for some babies jaundice becomes severe, a condition known as hyperbilirubinemia. There are several reasons this might happen, such as being born prematurely or having certain medical conditions. If not treated, severe jaundice can cause a type of permanent brain damage called kernicterus. Fortunately, this is rare.

Symptoms and Complications

When a newborn has jaundice, the condition is hard to miss: As the pigment circulates throughout the bloodstream the skin and whites of the eyes take on a yellow tint. The color sometimes begins on the face and then travels downward, to the chest, belly, legs, and soles of the feet. Most babies develop some degree of jaundice within two to four days of birth. This condition, known as physiological jaundice, usually resolves within a couple of weeks. When jaundice is severe, however, an infant may develop other symptoms. In fact, parents are typically instructed to keep an eye out for signs of severe jaundice after taking their newborn home from the hospital, including:

vomitinglethargynot feeding wellfeverhaving a high-pitched crydark urine or not enough wet or dirty diapers

When bilirubin levels become high enough to bring on these symptoms, a baby is at risk of developing kernicterus.

Causes and Risk Factors

There are a variety of reasons a baby might develop severe jaundice. The most common include:

Premature birth A blood group incompatibility with the mother Not feeding well Significant bruising at birth Jaundice appeared within the first 24 hours of life 

In some cases, jaundice can be attributed to certain conditions that cause red blood cells to break down. These conditions include:

Erythroblastosis fetalis (a blood disorder)Hemolytic anemia (a red blood cell disorder)

Diagnosis

For all newborns, bilirubin levels are somewhat elevated during the first few days of life. Many hospitals check total bilirubin levels on all babies at about 24 hours after birth, often using a probe that can estimate the levels simply by touching the skin.  The point at which a bilirubin level is dangerous changes with a baby’s age. A level of 7 m/dL at 5 hours old is very concerning, but a level of 16 m/dL may be fine for a baby who is 4 days old. If a baby’s bilirubin level is high, then blood tests are performed.

Treatment

Severe jaundice is treated with phototherapy. The baby is placed underneath special blue lights—bili lights—in a warm, enclosed bed wearing only a diaper and special eye shades. It usually takes only a day or two of phototherapy in the hospital to bring bilirubin levels down to normal. During that time frequent feeding—up to 12 times a day—is encouraged: With each bowel movement, more bilirubin is removed from the baby’s system. In rare cases, a baby may receive extra fluids intravenously. In the most severe cases of jaundice, an exchange transfusion is required as well. In this procedure, the baby’s blood is replaced with fresh blood. Giving intravenous immunoglobulin to babies who have severe jaundice may also be effective in reducing bilirubin levels.