Antenatal care: aneuploidy screening: practice question

A OBG question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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OBG · Antenatal care: aneuploidy screening

Sample item

Which combination on the second-trimester quadruple test is most suggestive of Down syndrome?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Low AFP, low unconjugated oestriol, high hCG, high inhibin A

In trisomy 21 the quad test shows low AFP, low uE3, raised hCG and raised inhibin A. Trisomy 18 gives all four markers low. High AFP points towards open neural tube defects or abdominal wall defects.

Option by option

  • A. High AFP with normal hCG and inhibin A

    Isolated high AFP suggests a neural tube defect or wrong dates.

  • B. High AFP, high oestriol, low hCG, low inhibin A

    This pattern is the reverse of the Down syndrome pattern.

  • C. Low AFP, low unconjugated oestriol, high hCG, high inhibin A (correct)

    Correct. This is the classic Down syndrome pattern.

  • D. Low AFP, low oestriol, low hCG, low inhibin A

    All four markers low is typical of trisomy 18.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this OBG question

What is the answer to this OBG question?

The best answer is C, Low AFP, low unconjugated oestriol, high hCG, high inhibin A. In trisomy 21 the quad test shows low AFP, low uE3, raised hCG and raised inhibin A.

Why is "High AFP with normal hCG and inhibin A" not the answer?

Isolated high AFP suggests a neural tube defect or wrong dates.

Why is "High AFP, high oestriol, low hCG, low inhibin A" not the answer?

This pattern is the reverse of the Down syndrome pattern.

Why is "Low AFP, low oestriol, low hCG, low inhibin A" not the answer?

All four markers low is typical of trisomy 18.

What concept does this question test?

It tests Antenatal care: aneuploidy screening in OBG. Trisomy 18 gives all four markers low. High AFP points towards open neural tube defects or abdominal wall defects.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Antenatal care: aneuploidy screening?

Learn management algorithms as steps: PPH, eclampsia, ectopic pregnancy. Then use the flashcards and the other OBG questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.