Antenatal care: Doppler in fetal anaemia: 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: Doppler in fetal anaemia

Sample item

In a pregnancy with Rh alloimmunisation, which Doppler measurement is used to non-invasively predict moderate to severe fetal anaemia?

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

The answer and the reasoning

C. Middle cerebral artery peak systolic velocity

Raised MCA peak systolic velocity above 1.5 multiples of the median predicts moderate to severe fetal anaemia because of reduced blood viscosity and increased cardiac output. It has largely replaced amniotic fluid delta OD450 for monitoring. Intrauterine transfusion is considered if raised.

Option by option

  • A. Ductus venosus a-wave

    The ductus venosus a-wave reflects cardiac function in severe growth restriction.

  • B. Uterine artery notching

    Uterine artery notching is a marker for pre-eclampsia risk.

  • C. Middle cerebral artery peak systolic velocity (correct)

    Correct. MCA-PSV above 1.5 MoM is the standard non-invasive test.

  • D. Umbilical artery systolic to diastolic ratio

    The umbilical artery S/D ratio reflects placental resistance in growth restriction.

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, Middle cerebral artery peak systolic velocity. Raised MCA peak systolic velocity above 1.

Why is "Ductus venosus a-wave" not the answer?

The ductus venosus a-wave reflects cardiac function in severe growth restriction.

Why is "Uterine artery notching" not the answer?

Uterine artery notching is a marker for pre-eclampsia risk.

Why is "Umbilical artery systolic to diastolic ratio" not the answer?

The umbilical artery S/D ratio reflects placental resistance in growth restriction.

What concept does this question test?

It tests Antenatal care: Doppler in fetal anaemia in OBG. 5 multiples of the median predicts moderate to severe fetal anaemia because of reduced blood viscosity and increased cardiac output. It has largely replaced amniotic fluid delta OD450 for monitoring. Intrauterine transfusion is considered if raised.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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: Doppler in fetal anaemia?

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.