Infertility: preimplantation genetic testing: 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 · Infertility: preimplantation genetic testing

Sample item

A couple who are both carriers of beta-thalassaemia wish to conceive by IVF and avoid an affected child without a later termination. Which technique is suitable?

AAmniocentesis at 16 weeks onlyBPGT-A for aneuploidy aloneCPreimplantation genetic testing for monogenic disease (PGT-M) on embryo biopsyDIntrauterine insemination

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

The answer and the reasoning

C. Preimplantation genetic testing for monogenic disease (PGT-M) on embryo biopsy

PGT-M tests a trophectoderm biopsy from embryos for the known familial mutation, so only unaffected embryos are transferred. PGT-A screens for chromosome number, and PGT-SR is for structural rearrangements. Prenatal diagnosis is still advised to confirm the result.

Option by option

A. Amniocentesis at 16 weeks only
Amniocentesis diagnoses after conception and may lead to termination.
B. PGT-A for aneuploidy alone
PGT-A does not test for the specific mutation.
C. Preimplantation genetic testing for monogenic disease (PGT-M) on embryo biopsy (correct)
Correct. PGT-M selects unaffected embryos for a known monogenic condition.
D. Intrauterine insemination
IUI does not allow selection of embryos.

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.

Questions about this OBG question

What is the answer to this OBG question?

The best answer is C, Preimplantation genetic testing for monogenic disease (PGT-M) on embryo biopsy. PGT-M tests a trophectoderm biopsy from embryos for the known familial mutation, so only unaffected embryos are transferred.

Why is "Amniocentesis at 16 weeks only" not the answer?

Amniocentesis diagnoses after conception and may lead to termination.

Why is "PGT-A for aneuploidy alone" not the answer?

PGT-A does not test for the specific mutation.

Why is "Intrauterine insemination" not the answer?

IUI does not allow selection of embryos.

What concept does this question test?

It tests Infertility: preimplantation genetic testing in OBG. PGT-A screens for chromosome number, and PGT-SR is for structural rearrangements. Prenatal diagnosis is still advised to confirm the result.

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 Infertility: preimplantation genetic testing?

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.