Question

Erythroblastosis foetalis occurs when:

• A. Mother is Rh negative and father is Rh positive.
• B. Father is Rh negative and mother is Rh positive.
• C. Both are Rh positive.
• D. Both are Rh negative.

Answer 1

The correct option is A Mother is Rh negative and father is Rh positive.

Erythroblastosis foetalis is a condition where the Anti-Rh antibodies produced in a mother with Rh-ve blood group will attack the foetal RBCs (hemolysis) and ultimately kills the foetus. Such a situation actually arises when an Rh${}^{-}$ mother is impregnated by an Rh${}^{+}$ father resulting in the conception of an Rh${}^{+}$ baby. If the woman is pregnant with her first baby, Rh incompatibility is not much of a concern because the mother is not exposed to significant amounts of foetal blood during the first pregnancy. However, at the time of delivery, there is a mixing of mother and fetal blood and the mother develops Anti-Rh antibodies over a period of time. In a situation where she gets impregnated a second time and carries a Rh+ve baby, the Anti-Rh antibodies will attack the foetus. Thus, the correct answer is option A.