Gestational trophoblastic disease: 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 · Gestational trophoblastic disease

Sample item

What is the usual karyotype of a complete hydatidiform mole?

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

The answer and the reasoning

B. 46,XX, entirely paternal in origin

A complete mole usually results from an empty egg fertilised by one sperm that then duplicates, giving 46,XX with only paternal chromosomes. A partial mole is triploid, for example 69,XXY, and often contains fetal tissue.

Option by option

  • A. 46,XY, maternal in origin

    A maternal-only contribution is not how a complete mole arises.

  • B. 46,XX, entirely paternal in origin (correct)

    Correct. All genetic material comes from the father.

  • C. 69,XXY

    69,XXY is a typical partial mole karyotype.

  • D. 45,X

    45,X is Turner syndrome and not related to molar pregnancy.

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 B, 46,XX, entirely paternal in origin. A complete mole usually results from an empty egg fertilised by one sperm that then duplicates, giving 46,XX with only paternal chromosomes.

Why is "46,XY, maternal in origin" not the answer?

A maternal-only contribution is not how a complete mole arises.

Why is "69,XXY" not the answer?

69,XXY is a typical partial mole karyotype.

Why is "45,X" not the answer?

45,X is Turner syndrome and not related to molar pregnancy.

What concept does this question test?

It tests Gestational trophoblastic disease in OBG. A partial mole is triploid, for example 69,XXY, and often contains fetal tissue.

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 Gestational trophoblastic disease?

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.