The cause of jaundice is a yellow bile pigment called bilirubin, which is carried in the blood and deposited in the skin, mucous membranes, and sclera (whites of the eyes). The result is that these areas of the body turn yellow.
Anything that causes a significant increase in the amount of bilirubin in the blood will lead to jaundice.
More than 25 percent of all healthy, full-term newborns become slightly jaundiced, usually on the third or fourth day of life. In premature babies the incidence of jaundice is higher.
The exact level of bilirubin in the blood is determined by a simple blood test.
No one can predict with certainty whether a newborn will develop jaundice, but Asian and Native American babies tend to have higher bilirubin levels than white babies, who have higher levels than black infants.
Breastfed babies are more likely to develop jaundice than those who are fed formula, although researchers are not certain why. Some older studies have suggested that breastmilk contains a hormone that inhibits the liver's ability to process bilirubin, but more recent research has shown no link between hormones in breast milk and liver function. Still, in many instances, if breastfeeding is discontinued for 24 hours and formula is substituted, bilirubin levels decline and "breastfeeding jaundice" clears up more rapidly.
The frequency of bowel movements also has been associated with jaundice. An infant's stool contains bilirubin, and if he passes stool too infrequently, some of the pigment is reabsorbed into the bloodstream and must be reprocessed by the liver, prolonging the symptoms of jaundice.
The two most common causes of jaundice in the newborn are an immaturity of the baby's liver, which is known as physiologic jaundice, and blood-group incompatibilities. There are many other, less common causes of jaundice in the newborn.
Doctors diagnose jaundice through a simple blood test. A bilirubin level of less than 12 milligrams per deciliter of blood in the first few weeks of life is generally considered normal for a healthy, full-term baby.
Doctors determine whether a newborn needs treatment for jaundice based “risk factors” and the baby’s age. Risk factors include jaundice in the first day of life, gestational age less than 38 weeks, mothers and babies blood being incompatible, brother or sister had jaundice after birth, male, collection of blood under the scalp, mother more than 25 years old, high blood counts, east Asian ethnicity and very high birth weight. Recommendations are:
Low risk: No risk factors - phototherapy should be started if bilirubin is greater than 12 (24 hours), 15 (48 hours), or 18 (72 hours) mg/dL
Medium risk: Term baby with risk factors or less than 38 weeks with no risk factors - phototherapy should be started if bilirubin is greater than 10 (24 hours), 13 (48 hours), or 15 (72 hours) mg/dL
High risk: Baby 35-37 weeks gestation with risk factors - phototherapy should be started if bilirubin greater than 8 (24 hours), 11 (48 hours), or 13 (72 hours) mg/dL
A major concern with jaundice is the risk of very high concentrations of bilirubin reaching the brain and causing damage. But studies show that most babies who suffer such brain damage have underlying illnesses or conditions, such as complete inability of the liver to process bilirubin.
Doctors usually use phototherapy, or light treatment, to bring down bilirubin levels. The infant is placed under special fluorescent lamps that convert the excess bilirubin into a water-soluble form that can be excreted in bile and urine. The infant receives treatment usually in an incubator, for approximately two to three days. During that period, parents can take the baby out of the incubator for feeding, or they can reach in and touch their child.
In some instances, hospitals are able to arrange for parents to rent home phototherapy equipment - long fluorescent lights that hang over the crib. Some hospitals are offering a fiber-optic "blanket" - a sheet of plastic that has fiber-optic tubing running through it so that the entire blanket becomes a light source. Many parents prefer the blanket because they are able to hold and cuddle their baby during treatment. Doctors will decide based on the baby’s risk factors and bilirubin levels if treatment at home is safe.
If bilirubin levels remain high or doctors are concerned that the baby will be at risk for worsening jaundice, they may recommend “intensive phototherapy” that includes the entire baby’s body. In very severe cases, they have to perform an exchange transfusion (remove some of the baby’s blood and replace it with a transfusion).
During phototherapy, it is very important to ensure the baby received plenty of fluids in the form of breast milk or formula or IV fluids. He should also where protective eye wear.