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

Step 1 : Understanding the Question:
The question asks us to identify the {incorrect} statements regarding Rh blood group incompatibility and its clinical consequences during pregnancy (erythroblastosis foetalis).
Step 2 : Key Formulas and Approach:
1. Rh status: $Rh^{+ve}$ (antigen present) and $Rh^{-ve}$ (antigen absent).
2. Sensitization: Occurs when an $Rh^{-ve}$ individual is exposed to $Rh^{+ve}$ blood.
3. Pregnancy rule: Incompatibility arises {only} if mother is $Rh^{-ve}$ and fetus is $Rh^{+ve}$.
Step 3 : Detailed Explanation:

Statement A: Erythroblastosis foetalis occurs when an $Rh^{-ve$ mother} carries an $Rh^{+ve$ fetus}. Statement A incorrectly swaps the Rh types. Thus, it is incorrect.

Statement B: About 80% of humans possess the Rh antigen, making them $Rh^{+ve}$. This statement is correct.

Statement C: Rh compatibility is crucial in blood transfusions to avoid a severe immune response (agglutination). This statement is correct.

Statement D: This correctly defines the condition for Rh incompatibility in pregnancy. This statement is correct.

Statement E: To prevent sensitization, anti-Rh antibodies must be administered immediately after the delivery of the first child (and subsequent ones). Waiting until the second child is too late, as the mother is already sensitized. Thus, it is incorrect.

Step 4 : Final Answer:
Based on the analysis, statements A and E are incorrect. This combination is found in option (C).