Nutrition: folic acid and neural tube defects: practice question

A PSM 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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PSM · Nutrition: folic acid and neural tube defects

Sample item

A 28-year-old woman whose previous baby had a myelomeningocele is planning another pregnancy. Which folic acid regimen is recommended to reduce recurrence?

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

The answer and the reasoning

A. 4 mg daily, starting at least a month before conception and continued through the first trimester

Folic acid taken around conception lowers the risk of neural tube defects, which arise by about the sixth week when the neural tube closes. The usual dose for women at average risk is 400 micrograms daily, while those with a previously affected child need a higher dose of 4 mg daily. Supplementation must begin before conception and cover the first trimester.

Option by option

  • A. 4 mg daily, starting at least a month before conception and continued through the first trimester (correct)

    Correct. A previous neural tube defect calls for the high 4 mg dose started before conception.

  • B. 1 g daily for the last trimester only

    Giving folic acid only in the last trimester comes long after the neural tube has closed.

  • C. 40 mg daily throughout pregnancy

    40 mg is far above the recommended dose and has no evidence of added benefit.

  • D. 400 micrograms daily, starting at the first antenatal visit

    400 micrograms is the dose for average-risk women, and starting late misses neural tube closure.

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 PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is A, 4 mg daily, starting at least a month before conception and continued through the first trimester. Folic acid taken around conception lowers the risk of neural tube defects, which arise by about the sixth week when the neural tube closes.

Why is "1 g daily for the last trimester only" not the answer?

Giving folic acid only in the last trimester comes long after the neural tube has closed.

Why is "40 mg daily throughout pregnancy" not the answer?

40 mg is far above the recommended dose and has no evidence of added benefit.

Why is "400 micrograms daily, starting at the first antenatal visit" not the answer?

400 micrograms is the dose for average-risk women, and starting late misses neural tube closure.

What concept does this question test?

It tests Nutrition: folic acid and neural tube defects in PSM. The usual dose for women at average risk is 400 micrograms daily, while those with a previously affected child need a higher dose of 4 mg daily. Supplementation must begin before conception and cover 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 Nutrition: folic acid and neural tube defects?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.