Pathologic jaundice involves a higher level of bilirubin and requires treatment to hasten the removal of bilirubin. This can occur in any newborn who has an exaggerated form of physiologic (normal) jaundice.

Prematurity:
Babies born more than two weeks before their due date is more likely to develop higher levels of bilirubin. The more premature a child is, the less mature their liver is at the time of birth, and the harder it is for them to start eliminating the bilirubin.

Blood type incompatibility:
This exists when a mother has the blood type O (and therefore has antibodies against A and B cells) and her newborn is of blood type A or B. This may cause the newborn’s red blood cells to break down more quickly due to maternal antibodies that have leaked into the baby’s bloodstream.
It also exists if the mother has a Rh (Rhesus) factor negative blood type and the newborn is Rh factor positive. This had been a common cause of severe neonatal jaundice, but is now very uncommon because Rh immune globulin (Rhogham) is given to mothers at risk before delivery.
A physical exam is always important in assessing the level of jaundice. Jaundice first appears on the face, and, as the bilirubin level rises, spreads down the body. The yellow color is best appreciated in natural light, so doing the exam by a window is helpful. Estimation of the level of jaundice by exam alone, however, is difficult and prone to errors. By obtaining blood though a prick of a newborn’s heel, an exact bilirubin level can be obtained.

Extremely high levels of bilirubin can lead to the rare but serious condition of kernicterus, a form of brain damage. This is now a very rare condition with most cases occurring in premature or very ill babies. Treatment for jaundice starts at levels that are far lower than those that could cause kernicterus.

ABO incompatibility can occur only if a woman with type O blood has a baby whose blood is type A, type B, or type AB. If a baby is type O there won’t be a problem with a negative immune response because type O blood cells don’t have immune-response triggering antigens. The most common problem caused by ABO incompatibility is jaundice. Jaundice occurs when there’s a buildup of an orangish-red substance in the blood called bilirubin that’s produced when red blood cells break down naturally. If more red blood cells are broken down at once than is normal, the bilirubin that results will deposit fatty tissue under the skin, causing the yellowish hue of the skin and whites of the eyes that are the tell-tale symptom of jaundice. Not every baby with ABO incompatibility will develop jaundice, and not every baby with jaundice will require extensive treatment. It will depend on how much bilirubin collects in the baby’s blood. Some infants with mild jaundice will get better on their own simply by being fed more often.

A temporary increase in feedings will lead to an increase in bowel movements, which is how excess bilirubin exits the body. Nursing mothers may need to supplement their baby’s diet with a formula for a few days if nursing alone doesn’t do the trick. For infants whose jaundice is more severe, photo-therapy, or light therapy, is effective.
The American Academy of Pediatrics guidelines dictate which newborns should be treated for jaundice. The necessity of treatment depends upon the bilirubin level, the newborn’s age in hours and the baby’s gestation. In general, the older the newborn, the higher the bilirubin level can be and not require treatment. For newborns with particular risk factors, such as prematurity, treatment is started at lower bilirubin levels for a given age in hours.
The baby’s skin is exposed to light waves that transform the bilirubin into a substance that can pass through the baby’s system. The baby will literally be placed under the light wearing just a diaper and soft eye patches. Instead of, or in addition to, photo-therapy a baby with jaundice may be treated with Bili blanket which uses fiber optics to break down bilirubin. The blue light converts the bilirubin into a form that can be removed from the body through the urine and bowel movements.
Since bili-blankets are available for home use, many newborns can be treated for jaundice at home. Whether a baby is a candidate for home phototherapy depends on the level of the bilirubin and the reasons for the jaundice. Treatment generally takes several days.

In rare cases, a baby with an HDN (hemolytic disease of the newborn) will need to be treated with a type of blood transfusion called an exchange transfusion. This is when a portion of a baby’s blood is replaced with type O blood. And a child who becomes severely anemic as a result of an HDN may need a more traditional transfusion in which he’s given extra blood to replace blood that’s lost.