The first child of `Rh^(+)` father and `Rh^(-)` mother is homozygous recessive condition. Is the next child affected by Erythroblastosis foctalis? Glven reason for your answer.

Explanation

I. When a pregnant women is `Rh^(-)` and the foetus is `Rh^(+)` incompatibility (mismatch) is observed.
2. During the first pregnancy, the `Rh^(-)` antigens of the foctus does not get exposed to the mother.s blood as both their blood are separated by placenta.
3. However, small amount of the foetal antigen becomes exposed to the mother.s blood during the birth of the first child.
4. The mother.s blood starts to synthesize Dantibodies. But during subsequent pregnancies the Rh antibodies from the mother (Rh) enters the foetal circulation and destroys the foetal RBCs.
5. This becomes fatal to the foctus because the child suffers from anaemia and jaundice. This condition is called erythroblastosis foetalis. This condition can be avoided by administration of anti D antibodies (Rhocum) to the mother immediately after the first child birth.