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How does erythroblastosis fetalis destroy a fetus's red blood cells?
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blood group
The major component of human blood is the red blood cell.
Erythroblastosis fetalis occurs due to a blood group incompatibility between a mother and her fetus, most commonly involving the Rh system. The process of destroying the fetus's red blood cells involves the following steps:
- Sensitization: If an Rh-negative mother carries an Rh-positive fetus, fetal red blood cells carrying the Rh factor (an antigen) may enter the mother's bloodstream, typically during labor. This exposure stimulates the mother's immune system to produce specific antibodies against the Rh factor.123
- Antibody Transfer: In subsequent pregnancies with an Rh-positive fetus, these maternal antibodies cross the placenta and enter the fetal circulation.123
- Hemolysis: Once in the fetal bloodstream, the maternal antibodies bind to the fetal red blood cells and cause them to lyse, or break apart. This destruction of red blood cells is known as hemolysis, which leads to anemia and other severe complications for the fetus or newborn.143