Complications of pregnancy: hypothyroidism: 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 · Complications of pregnancy: hypothyroidism

Sample item

A woman on stable levothyroxine for hypothyroidism has a positive pregnancy test. What is the correct adjustment?

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

The answer and the reasoning

A. Increase the dose by about 25 to 30 per cent and check TSH every 4 weeks

Thyroid hormone requirements rise by 25 to 50 per cent in pregnancy because of increased TBG and oestrogen effect. The dose is increased promptly (often by taking two extra tablets per week) and TSH is monitored every 4 weeks in the first half. The TSH target is within the trimester-specific range, usually below 2.5 mIU/L.

Option by option

  • A. Increase the dose by about 25 to 30 per cent and check TSH every 4 weeks (correct)

    Correct. Early dose escalation protects fetal neurodevelopment.

  • B. Continue the same dose and check TSH at 36 weeks

    Waiting until 36 weeks leaves the mother under-treated for months.

  • C. Stop levothyroxine in the first trimester

    Stopping would cause maternal and fetal hypothyroidism.

  • D. Switch to carbimazole

    Carbimazole is an antithyroid drug and not for hypothyroidism.

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 A, Increase the dose by about 25 to 30 per cent and check TSH every 4 weeks. Thyroid hormone requirements rise by 25 to 50 per cent in pregnancy because of increased TBG and oestrogen effect.

Why is "Continue the same dose and check TSH at 36 weeks" not the answer?

Waiting until 36 weeks leaves the mother under-treated for months.

Why is "Stop levothyroxine in the first trimester" not the answer?

Stopping would cause maternal and fetal hypothyroidism.

Why is "Switch to carbimazole" not the answer?

Carbimazole is an antithyroid drug and not for hypothyroidism.

What concept does this question test?

It tests Complications of pregnancy: hypothyroidism in OBG. The dose is increased promptly (often by taking two extra tablets per week) and TSH is monitored every 4 weeks in the first half. The TSH target is within the trimester-specific range, usually below 2.5 mIU/L.

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 Complications of pregnancy: hypothyroidism?

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.