Multiple pregnancy: chorionicity: 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 · Multiple pregnancy: chorionicity

Sample item

On ultrasound at 12 weeks, a twin pregnancy shows a thin membrane meeting the placenta in a T shape without a triangular projection. What does this indicate?

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

The answer and the reasoning

D. Monochorionic diamniotic twins

The T sign (no chorionic tissue extending between the layers) indicates monochorionic diamniotic twins. The lambda or twin-peak sign with a chorionic tissue triangle indicates dichorionic twins. Chorionicity is best determined in the first trimester.

Option by option

  • A. Conjoined twins

    Conjoined twins have fused bodies.

  • B. Monochorionic monoamniotic twins

    Monoamniotic twins lack a dividing membrane.

  • C. Dichorionic diamniotic twins

    The lambda sign denotes dichorionic twins.

  • D. Monochorionic diamniotic twins (correct)

    Correct. The T sign denotes monochorionic diamniotic twins.

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.

More OBG questions

Questions about this OBG question

What is the answer to this OBG question?

The best answer is D, Monochorionic diamniotic twins. The T sign (no chorionic tissue extending between the layers) indicates monochorionic diamniotic twins.

Why is "Conjoined twins" not the answer?

Conjoined twins have fused bodies.

Why is "Monochorionic monoamniotic twins" not the answer?

Monoamniotic twins lack a dividing membrane.

Why is "Dichorionic diamniotic twins" not the answer?

The lambda sign denotes dichorionic twins.

What concept does this question test?

It tests Multiple pregnancy: chorionicity in OBG. The lambda or twin-peak sign with a chorionic tissue triangle indicates dichorionic twins. Chorionicity is best determined in the first trimester.

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 Multiple pregnancy: chorionicity?

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.