Physiologic jaundice of the newborn, the most common cause of newborn jaundice, is present to some degree in almost all newborns. At birth, babies have relatively immature liver function.

Therefore, even the normal destruction of red blood cells by the liver in the newborn infant can cause jaundice. This form of jaundice usually appears between the 2nd and 5th days of life and clears by 2 weeks. It usually causes no problems.

Breast-feeding jaundice is seen in 5-10% of newborns. It is similar to physiologic jaundice, but bilirubin levels tend to be slightly higher. This occurs when breast-fed babies do not take in enough breast milk and rarely requires treatment.

Sometimes, however, breast-feeding does need to be interrupted and bottle-feeding substituted for a brief period of time to clear the jaundice.

Jaundice in a newborn is rarely caused by a serious illness. Disorders which can cause jaundice in a baby include:

• biliary atresia
• ABO incompatibility (similar to a transfusion reaction, caused when fetal and maternal blood mingle before birth)
• Rh incompatibility (Anti-Rh antibodies)
• galactosemia (see galactosemia screen)
• cephalohematoma
• polycythemia
• glucose-6-phosphate dehydrogenase deficiency
• neonatal sepsis
• congenital cytomegalovirus infection (CMV)
• congenital toxoplasmosis
• congenital syphilis
• congenital herpes
• congenital rubella
• late pregnancy administration of sulfa drugs to the mother
• Crigler-Najjar syndrome
• spherocytosis (congenital hemolytic anemia)
• cystic fibrosis
• pyruvate kinase deficiency
• thalassemia
• Gilbert's syndrome
• congenital hypothyroidism
• Lucey-Driscol syndrome
• Gaucher's disease
• Niemann-Pick disease

• yellow color of the skin (jaundice)
• poor feeding (may be present)
• lethargy (may be present)

• elevated serum bilirubin level

Treatment is usually unnecessary. In all cases, it is important to keep the baby well-hydrated (breast milk and formula are preferable to glucose water) and encourage frequent bowel movements by feeding frequently. This is because broken down bilirubin is carried out of the body by the intestines in the stools (bilirubin is what gives stool their brown color).

Sometimes artificial lights are used on infants whose levels are very high, or in premature infants. These lights work by helping to break down bilirubin in the skin. The infant is placed naked under artificial light in a protected isolette to maintain constant temperature. The eyes are protected from the light.

In the most severe cases of jaundice, an exchange transfusion is required. In this procedure, the baby's blood is replaced with fresh blood. Recently, promising studies have shown that treating severely jaundiced babies with intravenous immunoglobulin is very effective at reducing the bilirubin levels to safe ranges.

Physiologic jaundice is a normal occurrence and probably not preventable. Prevention of disease-related jaundice is related to the specific disease (see the specific disease).

Since babies are now sent home from the hospital quickly or are often born in settings like birthing centers, it is important for parents to be on the lookout for jaundice in their infants in the first few weeks of life.