Question

Explain Rh-incompatibility in humans.

Answer 1

A special case of Rh-incompatibility (mismatching) has been observed between the Rh-negative blood of a pregnant mother and with Rh-positive blood of the foetus. Rh antigens of the foetus do not get exposed to the Rh-negative blood of the mother in the first pregnancy as the two types of blood are well separated by the placenta. However, during the delivery of the first child, there is a possibility of exposure of the maternal blood to small amounts of the Rh – positive blood from the foetus. In such cases, the mother starts preparing antibodies against Rh antigen in her blood. In the case of her subsequent pregnancies, the Rh antibodies from the mother (Rh-negative) can leak into the blood of the foetus (Rh-positive) and destroy the foetal RBCs. This could be fatal to the foetus or could cause severe anaemia and jaundice in the baby. This condition is called erythroblastosis foetal. This can be avoided by administering anti-Rh antibodies to the mother immediately after the delivery of the first child.