What Is Erythroblastosis Fetalis?
The adult human body is home to trillions of red blood cells (also known as erythrocytes or RBCs). These blood cells carry oxygen, iron, and many other nutrients to the appropriate places in the body. When a woman is pregnant.
it’s possible that her baby’s blood type will be incompatible with her own. This can cause a condition known as erythroblastosis fetalis, where the mother’s white blood cells attack the baby’s red blood cells as they would any foreign invaders.
What are the symptoms of erythroblastosis fetalis?
Babies who experience erythroblastosis fetalis symptoms may appear swollen, pale, or jaundiced after birth. A doctor may find that the baby has a larger-than-normal liver or spleen. Blood tests can also reveal that the baby has anemia or a low RBC count. Babies can also experience a condition known as hydrops fetalis, where fluid starts to accumulate in spaces where fluid is normally not present. This includes spaces in the:
This symptom can be harmful because the extra fluid places pressure on the heart and affects its ability to pump.
What causes erythroblastosis fetalis?
In addition, blood can be either Rh positive or Rh negative. For example, if you’re type A and Rh positive, you have A antigens and Rh factor antigens on the surface of your RBCs. Antigens are substances that trigger an immune response in your body.
If you have AB negative blood, then you have both A and B antigens without the Rh factor antigen.
Rh incompatibility occurs when a Rh-negative mother is impregnated by a Rh-positive father. The result can be a Rh-positive baby. In such a case, your baby’s Rh antigens will be perceived as foreign invaders, the way viruses or bacteria are perceived. Your blood cells attack the baby’s as a protective mechanism that can end up harming the child.
If you’re pregnant with your first baby, Rh incompatibility isn’t as much of a concern. However, when the Rh-positive child is born, your body will create antibodies against the Rh factor. These antibodies will attack the blood cells if you ever become pregnant with another Rh-positive baby.
Another type of blood type mismatch that can cause maternal antibodies against her baby’s blood cells is ABO incompatibility. This occurs when the mother’s blood type of A, B, or O isn’t compatible with the baby’s.
This condition is almost always less harmful or threatening to the baby than Rh incompatibility. However, babies can carry rare antigens that can put them at risk for erythroblastosis fetalis. These antigens include:
How is erythroblastosis fetalis diagnosed?
To diagnose erythroblastosis fetalis, a doctor will order a routine blood test during your first prenatal visit. They’ll test for your blood type. The test will also help them determine whether you have anti-Rh antibodies in your blood from a previous pregnancy. The fetus’s blood type is rarely tested. It’s difficult to test for a fetus’s blood type and doing so can increase the risk for complications.
Frequency of testing
If initial testing shows your baby may be at risk for erythroblastosis fetalis, your blood will be continually tested for antibodies throughout your pregnancy — approximately every two to four weeks.
If your antibody levels start to rise, a doctor may recommend a test to detect fetal cerebral artery blood flow, which isn’t invasive to the baby. Erythroblastosis fetalis is suspected if the baby’s blood flow is affected.
If you have Rh-negative blood, the father’s blood will be tested. If the father’s blood type is Rh negative, no further testing is needed. However, if the father’s blood type is Rh positive or their blood type isn’t known, your blood may be tested again between 18 to 20 weeks of pregnancy, and again at 26 to 27 weeks. You’ll also receive treatment to prevent erythroblastosis fetalis.
If your baby is jaundiced after birth, but Rh incompatibility isn’t a concern, the baby may be experiencing problems due to ABO incompatibility. ABO incompatibility occurs most frequently when a mother with an O blood type gives birth to a baby who has an A, B, or AB blood type. Because O blood types may produce both A and B antibodies, the mother’s blood can attack the baby’s.