Dr. Greene's Answer
There are two types of jaundice that are related to breastfeeding. They are called breastfeeding jaundice and breast milk jaundice. Breastfeeding jaundice is a jaundice that may occur in the first week of life in breast-fed infants. 13% of breast-fed babies will develop jaundice in the first week of life (Nelson Textbook of Pediatrics, WB Saunders, 2007). The cause of breastfeeding jaundice is thought to be due to insufficient milk intake leading to dehydration or low caloric intake. The incidence of breast-feeding jaundice may be reduced by increasing the frequency of feeding and avoiding the use of water to replace breast milk (Nelson Textbook of Pediatrics, WB Saunders, 2007).
Breast milk jaundice is far less common, occurring in about 1 in 200 babies. Here the jaundice is often not visible until the baby is a week old and then reaches its peak during the second or third week. Breast milk jaundice is thought to be caused either by enzymes in mom’s milk that deactivate the baby’s enzyme for dealing with bilirubin or by fatty acids in mom’s milk that the baby processes as a priority over processing the bilirubin. Researchers are looking at other potential causes as well
Whichever the cause of breast milk jaundice, if the mother continues to nurse her baby, the jaundice will decrease and disappear on its own, but this may take 3 to 10 weeks. If the mother stops nursing for 1 or 2 days, substituting formula, the bilirubin levels will drop rapidly. They will typically not rise again when the nursing is resumed.
Permanent damage or ill effects from breast milk jaundice is extremely rare. Phototherapy (lights used to lower bilirubin) may be used if the level of bilirubin is above 20 mg/dL. In breast milk jaundice, stopping breast milk for 1 to 2 days can help the bilirubin level drop rapidly. However, pediatricians and neonatologists generally agree that most babies who are well enough to feed may continue to feed on breast milk. This is true even when the bilirubin level is high enough to require phototherapy.