Why is it necessary to check the Rh-factor of the blood of a pregnant woman?
Rh-antigen is present on the surface of erythrocytes in about 80-85% of human beings. The individuals who possess this antigen are called Rh-positive and those who do not have it are called Rh-negative. An Rh-negative person, when exposed to Rh-positive blood, develops anti-Rh- antibodies. If a pregnant woman who is Rh-negative, bears an Rh-positive foetus, will develop anti-Rh-antibodies during the first delivery when the foetal blood comes in contact with her blood. These antibodies linger in the blood for sufficiently long periods. If she carries a second foetus, that is Rh-positive, the anti-Rh-antibodies in her blood enter the foetal circulation and cause damage to the foetal RBCs, and could become fatal. This condition is called erythroblastosis foetalis.
