From The Parent Review
In the first week of life, many healthy newborns temporarily take on a yellowish, or jaundiced, tinge in their skin and the whites of their eyes. Called neonatal hyperbilirubinemia, or newborn jaundice, it usually appears on or around the third day, and is usually gone within a week or so.
Normal jaundice is the result of bilirubin, one of the breakdown products of old red blood cells. Until birth, the mother's placenta clears the fetal blood of most of the bilirubin. After birth, bilirubin is processed by the infant's liver, excreted into the intestines, and discharged along with the stool. As the newborn's body adjusts to life outside the uterus, however, the enzyme that processes the bilirubin in the baby's liver is just being produced and may be inadequate in some infants to meet the new demand of processing bilirubin. Unprocessed bilirubin cannot be excreted and is recycled in the bloodstream until it is processed by the liver.
In rare cases, severe jaundice can be a symptom of an underlying condition. The resulting huge overload of bilirubin can damage organs, most importantly the brain. The bilirubin level in such cases is generally far higher than that of babies experiencing normal or benign jaundice.
Breastfed babies are more likely to experience slight, or benign, jaundice in the first week of life. A recent survey of a large group of breastfed infants found a higher rate of jaundice in "early discharge" breastfed infants; that is, babies who have gone home with their mothers from the hospital within 24 to 48 hours after delivery.
In healthy infants, levels of bilirubin in the bloodstream depend on how often the bowels move, which itself depends on how soon and how often the baby has been fed. Mothers who leave the hospital within 24 to 48 hours of delivery, and the nurses and lactation consultants offering breastfeeding support, may not put newborns to the breast often enough in the first three days of life. Sometimes newborns are sleepy for a few days after birth and a mother needs additional support in learning to wake the baby and encouraging him or her to nurse. The newborn breastfed baby should get at least 11 to 12 feedings in each 24-hour period. Frequent feeding not only causes frequent bowel movements, but coats the infant's digestive track with milk fat, which protects against the reabsorption of bilirubin. To produce both bowel movements and internal coating, the frequency of feedings in the first days of life is more important than the quantity of milk ingested.
In one study on neonatal jaundice, researchers found that the bilirubin levels of breastfed babies could be cut in half, bringing them lower than the levels typical of bottlefed babies, simply by feeding the babies every two hours instead of every four. The authors of the study urged that all infants discharged within 72 hours of birth be seen by a healthcare professional by the third day at home, and that every breastfeeding mother be given effective support and information to get nursing going smoothly right from the start.
Sources: Pediatrics 113 (2004): 42-49; Pediatrics 101 (1998): 995-998.