Question

The problem, due to $R{h}^{+}$ factor arises when the blood of two ($R{h}^{+}$ and ${\mathrm{Rh}}^{-}$) mix up:

• A. In a test tube
• B. During pregnancy
• C. Both a and c
• D. Through transfusion

Answer 1

The correct option is C Both a and c

A protein named Rhesus antigen, is present on the surface of red blood corpuscles. Persons having this Rhesus antigen (Rh factor) are called Rh positive ($R{h}^{+}$ ).

Others who do not have this factor are known as Rh negative (${\mathrm{Rh}}^{-}$). Both $R{h}^{+}$ and ${\mathrm{Rh}}^{-}$ individuals are phenotypically normal.

The problem arises during blood transfusion and pregnancy. The first blood transfusion of $R{h}^{+}$ blood to the person with ${\mathrm{Rh}}^{-}$ blood causes no harm because the ${\mathrm{Rh}}^{-}$ person develops anti Rh factors or antibodies in his/her blood. In the second blood transfusion of $R{h}^{+}$ blood to the ${\mathrm{Rh}}^{-}$ person, the latter’s anti- Rh factors attack and destroy the red blood corpuscles of the donor.

During pregnancy, if the father's blood is $R{h}^{+}$, mother’s blood is ${\mathrm{Rh}}^{-}$ and the foetus blood is $R{h}^{+}$. Then in the second pregnancy (with $R{h}^{+}$ foetus), the anti- Rh factors of the mother’s blood destroy the foetal red blood corpuscles. This is called erythroblastosis foetalis( Haemolytic disease of the newborn).