Diseases & Conditions
A substance produced when red blood cells are broken down. Usually the bilirubin is taken up by the liver and then excreted. However, the liver of newborn babies is immature and cannot do a good job of getting rid of bilirubin, so it remains in the blood, making the skin appear yellow. These babies are then diagnosed with JAUNDICE, which is very common among newborns.
Occasionally the bilirubin level is so high it can be dangerous to the brain, especially if the mother’s and baby’s blood types are different. In addition to the A and B antigens possibly present on a baby’s red cells, there is another class of protein called the Rh antigen. If a mother has Rhnegative blood (which means she does not have the Rh antigen on her blood cells), but she carries a fetus whose blood type is Rh-positive, cells from the baby can migrate across the placental barrier and stimulate the production of a maternal antibody that can cross back into the baby’s system and trigger the destruction of the baby’s red blood cells. This is termed hemolytic anemia. The resultant ﬂood of bilirubin from the breakdown of these red cells overwhelms the baby’s ability to cleanse the bloodstream of bilirubin.
Usually, the abnormal antibody poses little threat to the ﬁrst Rh-positive baby born to an Rhnegative mother. However, subsequent Rh-positive babies are at risk. Fortunately, this problem is now very rare due to an immunization given to Rhnegative mothers after delivery of an Rh-positive baby. This shot (RhoGam) blocks the formation of high levels of the abnormal anti-Rh antibody and protects subsequent pregnancies with a high degree of efﬁciency. The degree of jaundice can be measured by a simple blood test. If treatment is necessary, allowing the newborn to sleep under ﬂuorescent lights or under a special “light blanket” usually resolves the problem.