This symbol for Rh antigen stands for ‘Rhesus’—a species of monkey which serves as the experimental animals for the discovery of this factor. This Rh factor is found in 85% white population.
If a person’s red blood cells contain the Rh antigen he is said to be Rh positive. If he has no Rh antigen then he is Rh negative.
Normally the blood of a Rh negative person does not carry any antibody that can react with this antigen or factor but such bodies may be produced if Rh negative blood comes across Rh positive blood.
If Rh positive blood is transfused into the body of Rh negative person the Rh positive red blood cells serve as foreign bodies to the Rh negative person and so his body proceeds to produce antibodies called anti-Rh agglutinin to destroy the foreign bodies, i.e., the Rh positive red blood cells.
One transfusion is not apt to be serious but repeated transfusions may result in severe reaction and ultimately the death of Rh negative person may be occurred.
The safest procedure, for the Rh negative person, is to receive only Rh negative blood. 93% Indian population is Rh positive, while the rest 7% is Rh negative.
Rh factor is very important factor as it is inheritable and consequently presents a serious problem if a Rh negative woman marries a Rh positive man.
When these two mate and woman conceives a Rh positive foetus in her uterus, Rh positive factor will pass into the circulatory system of the mother through the placenta and evoke Rh antibodies formation in the mother.
As the amount of Rh antibodies produced during first conception is small, the first Rh positive child will be normal but if this woman again becomes pregnant with Rh positive foetus the results will be disastrous because more Rh antibodies will be produced and some of these will pass through the placenta into the body of foetus.
Rh antibodies came from mother will react with Rh antigens present in the foetus red blood cells, thereby, causing agglutination of red cells which may result in the death of foetus or new born child.
The death of newly born child may be avoided by a continuous transfusion, i.e., all the blood of child is replaced by some donor’s blood.