Updated January 29, 2013.

Introduction

Jaundice is due to a buildup in the blood of bilirubin, a yellow pigment which comes from the breakdown of old red blood cells. It is normal for red blood cells to break down, but the bilirubin formed does not usually cause jaundice because the liver metabolizes it and gets rid of it into the gut. The newborn baby, however, often becomes jaundiced during the first few days because the liver enzyme which metabolizes bilirubin is relatively immature.

Furthermore, newborn babies have more red blood cells than adults, and thus more are breaking down at any one time. If the baby is premature, or stressed from a difficult birth, or the infant of a diabetic mother, or more than the usual number of red blood cells are breaking down (as happens in blood incompatibility), the level of bilirubin in the blood may rise higher than what is usual.

Two Types of Jaundice

The liver changes bilirubin so that it can be eliminated from the body. If, however, the liver is functioning poorly, as occurs during some infections, or the tubes which transport the bilirubin to the gut are blocked, this changed bilirubin may accumulate in the blood and also cause jaundice. When this occurs, the changed bilirubin (called conjugated bilirubin), appears in the urine and turns the urine brown. This brown urine is an important clue that the jaundice is not ?ordinary?. Jaundice due to conjugated bilirubin is always abnormal, frequently serious and needs to be investigated thoroughly and immediately.

Except in the case of a few extremely rare metabolic diseases, breastfeeding can and should continue.

Accumulation of bilirubin before it has been changed by the enzyme of the liver may be normal;?physiologic jaundice?. Physiologic jaundice begins on the 2nd or 3rd day, peaks on the 3rd or 4th day and then begins to disappear. However, there may be other conditions which cause an exaggeration of this type of jaundice, such as a more rapid than normal breakdown of red blood cells. Because these conditions have no association with breastfeeding, breastfeeding should continue. If, for example, the baby has severe jaundice due to rapid breakdown of red blood cells, this is not a reason to take the baby off the breast.