Hemolytic Disease of the Newborn

Every person’s blood type includes an Rh factor that is either positive or negative. Rh factor is a protein that can exist on the surface of red blood cells. People who have Rh factor have a positive blood type, such as B+. People who do not have the Rh factor have a negative blood type, such as B-.

Hemolytic disease of the newborn (HDN) occurs when a mother with Rh negative blood has an Rh positive baby. This incompatibility happens most often when the mother is Rh negative, the father is Rh positive, and the baby inherits the father’s Rh positive factor.

Here’s what can happen:

• The baby’s Rh positive blood cells may cross over to the mother. This happens most often at delivery, but may also happen at other times throughout the pregnancy as red blood cells cross the placenta.
• The mother’s immune system sees the Rh positive blood cells as intruders, and creates antibodies to attack them.
• The mother is now considered Rh sensitized. Her body keeps the antibodies in case they are needed in the future.

Complications of HDN

Rh factor incompatibility is not usually a problem in the first pregnancy, because the baby is delivered before the mother’s body can produce antibodies. But if the mother has another Rh positive baby, and their blood cells cross, her antibodies will attack the baby’s blood cells, which can make the baby anemic.

HDN can cause mild to severe complications:

• Anemia disrupts the blood’s ability to transport oxygen to the baby’s body and brain.
• The baby’s body quickly tries to make more red blood cells, but they are not mature enough.
• As the red blood cells break down, bilirubin is created and can build up in the baby’s blood and tissues. This can cause yellowing of the baby's skin (jaundice).
• Significantly excessive bilirubin can damage the baby’s organs and brain, and may be fatal.

Symptoms of HDN

Newborns who have hemolytic disease may have the following symptoms:

• Pale skin color due to anemia.
• Yellowing of the eyes, skin, umbilical cord or amniotic fluid (jaundice) within a day or two of birth.
• Swelling of the entire body.

Treating HDN

Mercy Kids physicians are experts in treating babies with HDN. Depending on the severity of the disease, treatment may include:

• Blood transfusions or exchanges to provide healthy blood cells and reduce bilirubin levels.
• Intravenous fluids to maintain blood pressure.
• Help with respiratory problems.
• Intravenous immunoglobin(IVIG) to strengthen the baby’s immune system and reduce bilirubin levels.

Preventing HDN

Women who are not Rh sensitized may take a drug known as Rh immunoglobulin (RhIg) or RhoGAM that prevents their antibodies from reacting to Rh positive blood cells.

Women who already are Rh sensitized are monitored throughout their pregnancy for signs of anemia in the fetus. If necessary, a blood transfusion may be given.