Question

Hydrops fetalis is due to?

• A. Rh mismatch
• B. Hyperproteinemia
• C. Placental hypoplasia
• D. All of the above

Hint:

Think of the immune (haemolytic) cause from blood-group incompatibility.

Answer 1

The Correct Option is A

Step 1: Hydrops fetalis is the abnormal accumulation of fluid in two or more fetal compartments, such as ascites, pleural effusion, pericardial effusion, and skin oedema. It is classified as immune or non-immune.

Step 2: The classic immune cause is Rh incompatibility (Rh mismatch). When an Rh-negative mother is sensitised to an Rh-positive fetus, maternal anti-D antibodies cross the placenta, destroy fetal red cells, and cause severe anaemia and high-output cardiac failure, producing immune hydrops. This makes Rh mismatch the correct answer.

Step 3: Why the other options are wrong: hyperproteinemia does not cause hydrops; if anything, low albumin (hypoproteinemia) would favour oedema, so the listed option is incorrect. Placental hypoplasia is not a standard direct cause of fetal hydrops. Because two of the listed options are not causes, all of the above is also incorrect.

Step 4: Hence Rh mismatch is the single correct cause among the options.