ABO incompatibility

ABO incompatibility is a type of hemolytic disease that occurs when the immune system of a newborn baby attacks its own red blood cells due to a mismatch between the mother's and baby's ABO blood group system. This condition is a potential cause of jaundice in newborns and, in severe cases, can lead to serious complications such as anemia, hyperbilirubinemia, and kernicterus. ABO incompatibility is distinct from Rh disease, another form of hemolytic disease of the fetus and newborn (HDFN), which is related to the Rh factor.

Causes and Risk Factors

ABO incompatibility arises when a mother's blood type is O, and her baby inherits an A, B, or AB blood type from the father. The mother's immune system may produce naturally occurring antibodies against the A and B antigens present on the baby's red blood cells, leading to hemolysis (destruction of red blood cells). This condition is more likely to occur in newborns of mothers with blood type O due to the presence of anti-A and anti-B antibodies in her plasma.

Symptoms

Symptoms of ABO incompatibility may include:

• Jaundice: Yellowing of the skin and whites of the eyes, typically appearing within the first 24 hours after birth.
• Anemia: A lower than normal number of red blood cells.
• Hepatosplenomegaly: Enlargement of the liver and spleen.
• Hyperbilirubinemia: Elevated levels of bilirubin in the blood.

Diagnosis

Diagnosis of ABO incompatibility involves several tests:

• Blood type testing of the mother and baby.
• Direct Coombs test: Detects antibodies attached to the surface of the baby's red blood cells.
• Bilirubin levels: Measured to assess the severity of jaundice.

Treatment

Treatment for ABO incompatibility may include:

• Phototherapy: Using light to break down bilirubin in the baby's skin.
• Intravenous immunoglobulin (IVIG): May reduce the need for phototherapy and exchange transfusion.
• Exchange transfusion: In severe cases, replacing the baby's blood with compatible blood to remove antibodies and bilirubin.

Prevention

There is no established method to prevent ABO incompatibility. However, early detection and treatment of jaundice can prevent severe complications.

Prognosis

The prognosis for infants with ABO incompatibility is generally good, especially with early treatment. Most infants recover completely without long-term effects.

See Also

• Hemolytic disease of the newborn
• Rh incompatibility
• Jaundice in newborns
• Blood transfusion