Question

Select the incorrect statements with reference to Rh grouping.
A. Erythroblastosis foetalis is a condition observed having foetus with $Rh^{-ve$ blood and mother with $Rh^{+ve}$ blood.
B. Rh antigen is observed on RBCs in the majority of human beings.
C. Before blood transfusion, Rh group should also be matched.
D. Rh incompatibility is observed when a pregnant mother is $Rh^{-ve}$ and the foetus is $Rh^{+ve}$.
E. Erythroblastosis foetalis can be avoided by administering anti-Rh antibodies to the mother immediately after the delivery of the second child.
Choose the answer from the options given below:}

• A. B and C only
• B. A and B only
• C. A and E only
• D. C and D only

Hint:

Logic Tip: For Rh incompatibility during pregnancy, remember the rule: "Negative Mom, Positive Baby". If Mom is Positive, she already recognizes the Rh protein as "self", so no attack will occur regardless of the baby's blood type.

Answer 1

The Correct Option is C

Concept:
The Rh (Rhesus) blood group system is a critical component of blood typing. Rh incompatibility occurs when there is a mismatch between the Rh factors of individuals, most notably during pregnancy or blood transfusions. Erythroblastosis fetalis (Hemolytic Disease of the Newborn) is a severe consequence of maternal-fetal Rh incompatibility.
Step 1:
Erythroblastosis fetalis occurs when an $Rh^{-ve$ mother} carries an $Rh^{+ve$ fetus}. The mother's immune system attacks the fetal red blood cells. Statement A has the Rh factors swapped (stating fetus is $Rh^{-ve}$ and mother is $Rh^{+ve}$), which would not cause an immune reaction. Thus, Statement A is incorrect.
Step 2:
The Rh antigen is present on the surface of RBCs in nearly 80% of the human population (these individuals are termed $Rh^{+ve}$). Thus, Statement B is correct.
Step 3:
Just like the ABO blood group, the Rh blood group must be strictly matched before a blood transfusion to prevent a severe immune response (transfusion reaction) where the recipient's body destroys the donor's RBCs. Thus, Statement C is correct.
Step 4:
As established in Step 1, physiological Rh incompatibility specifically arises when a pregnant mother lacks the Rh antigen ($Rh^{-ve}$) but her developing fetus possesses it ($Rh^{+ve}$). Thus, Statement D is correct.
Step 5:
To prevent the mother's immune system from becoming sensitized and producing permanent Rh antibodies, anti-Rh antibodies (like RhoGAM) must be administered to the $Rh^{-ve}$ mother immediately after the delivery of her first $Rh^{+ve}$ child, not the second. Delaying until the second child would be too late, as sensitization would have already occurred. Thus, Statement E is incorrect.
Step 6:
The question asks to identify the incorrect statements. Based on our evaluation, statements A and E are incorrect.