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High Bilirubin Levels and HDFN

Immediately after birth the birth, the concern is high bilirubin levels. Bilirubin is formed when blood cells die, so as the antibodies destroy the baby’s blood cells, the bilirubin builds up. Before delivery, the placenta filtered out the bilirubin. After birth, that job falls to the baby’s liver. The liver is immature and does not do a good job filtering out the bilirubin, as a result the bilirubin builds up. The baby’s blood-brain barrier is not fully developed yet at birth and bilirubin is toxic to the brain. All together (the immature liver and the immature blood-brain barrier), this is why the treatment levels are lower in babies who are 12 hours old vs those who are 12 days old. Bilirubin due to HDFN is considered to be more neurotoxic than bilirubin due to other causes. For this reason, babies with HDFN are considered to be at high risk (born before 38 weeks) or medium risk (born 38 weeks or later) for damage from high bilirubin. As a result, babies with HDFN need phototherapy treatment at lower levels. If the bilirubin isn’t controlled with lights, they will use IVIG (a medication) or an exchange transfusion to remove the bilirubin.  Most babies are over bili issues by 3 weeks old, and it is common for a child with HDFN to need lights for 10 -14 days or even longer. The American Academy of Pediatrics recommends that phototherapy for infants with HDFN only be done in a hospital. This is because the hospital lights are stronger than at home machines.

In the photos below, notice the yellow tinge to the baby’s skin. You can spot it especially near the eyes, nose, and sometimes cheeks. This yellowing of the skin is called jaundice. Many parents do not know that jaundice can be dangerous. Babies with HDFN should have their bilirubin levels checked regularly.

Anemia and HDFN

Because the antibodies are destroying the baby’s blood cells, they can cause anemia. There are 3 types of anemia due to HDFN: early onset, delayed onset, and hyporegenerative. In early onset anemia, the anemia is present at birth or within the first two weeks. These babies frequently come out anemic due to an elevated MoM score indicating delivery at/after 35 weeks, or after a failed IUT. In some cases, the anemia is missed on MCA scan and is picked up at birth. Like all anemia, this is treated with blood transfusion. Unlike in adults and other babies, anemia due to HDFN is NOT treated with iron. As the blood cells die, the iron is stored and recycled in the baby’s body causing iron to build up. This is often exacerbated by transfusing iron-rich adult blood. Giving iron supplements to an infant with HDFN can be very dangerous. This is why the medical literature recommends a ferritin test before iron supplementation for infants with HDFN. Delayed onset anemia is anemia that happens 2-12 weeks after birth. Weekly hemoglobin checks are a must according to the medical literature. During the time period of 2-6 weeks is when many babies need their first transfusion, and unfortunately some of them die or have permanent damage from anemia that was not caught in time. This tragedy is completely preventable with a weekly hemoglobin check. Usually after 6 weeks, if the baby hasn’t had a transfusion, they won’t need one, but the doctors should be monitoring just in case. Monitoring stops when baby has had two hemoglobin increases in a row.

The babies in this slideshow were all anemic and receiving blood transfusions. Notice how pale their lips and eyes were before transfusion. Some of these babies look pale, others look yellow from residual bilirubin.

HDFN causes Neutropenia and Thrombocytopenia

The two other side effects of HDFN are neutropenia (40-50% of babies) and thrombocytopenia (25% of babies with HDFN). These happen because the baby is so busy making new red blood cells that it stops making white blood cells (neutrophils) and platelets (thrombocytes). When neutropenia or thrombocytopenia happen in infants with HDFN, there is usually extra monitoring and precautions that the parents will need to take, but these conditions generally do not require treatment.

Now what?
After 12 weeks old, or whenever the baby is cleared from HDFN, the baby is usually perfectly healthy with no lasting side effects (assuming the proper monitoring and prompt treatment for any issues that did arise). Unless the baby experienced severe anemia or extremely high levels of bilirubin before treatment, there are no long-term neurological effects and the child does not have any issues. You can have a perfectly normal infant and child after HDFN.