Endocrinology: pituitary vulnerability in pregnancy: practice question

A Physiology 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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Physiology · Endocrinology: pituitary vulnerability in pregnancy

Sample item

After massive postpartum haemorrhage with shock, a woman cannot breastfeed and her periods never resume. Which feature of the pregnant pituitary makes it especially vulnerable to infarction?

ALactotroph hyperplasia enlarges the gland while its low-pressure portal supply fails in shockBRaised prolactin in pregnancy reduces hypothalamic blood flowCA high-pressure arterial supply delivered directly to the anterior lobeDSwelling of the posterior lobe compresses the portal veins

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

The answer and the reasoning

A. Lactotroph hyperplasia enlarges the gland while its low-pressure portal supply fails in shock

In pregnancy oestrogen causes lactotroph hyperplasia and the pituitary enlarges. The anterior lobe is supplied by a low-pressure portal system, so severe hypotension can cause ischaemic necrosis. Loss of prolactin gives failure of lactation and loss of gonadotrophins gives amenorrhoea.

Option by option

A. Lactotroph hyperplasia enlarges the gland while its low-pressure portal supply fails in shock (correct)
Correct. An enlarged gland perfused by a low-pressure portal system is easily infarcted in shock.
B. Raised prolactin in pregnancy reduces hypothalamic blood flow
Prolactin does not reduce hypothalamic perfusion; the problem is pituitary ischaemia after haemorrhage.
C. A high-pressure arterial supply delivered directly to the anterior lobe
The anterior lobe is supplied by a low-pressure portal system, not a high-pressure direct arterial supply.
D. Swelling of the posterior lobe compresses the portal veins
The posterior lobe does not swell enough to compress the portal vessels in this way.

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 Physiology question

What is the answer to this Physiology question?

The best answer is A, Lactotroph hyperplasia enlarges the gland while its low-pressure portal supply fails in shock. In pregnancy oestrogen causes lactotroph hyperplasia and the pituitary enlarges.

Why is "Raised prolactin in pregnancy reduces hypothalamic blood flow" not the answer?

Prolactin does not reduce hypothalamic perfusion; the problem is pituitary ischaemia after haemorrhage.

Why is "A high-pressure arterial supply delivered directly to the anterior lo…" not the answer?

The anterior lobe is supplied by a low-pressure portal system, not a high-pressure direct arterial supply.

Why is "Swelling of the posterior lobe compresses the portal veins" not the answer?

The posterior lobe does not swell enough to compress the portal vessels in this way.

What concept does this question test?

It tests Endocrinology: pituitary vulnerability in pregnancy in Physiology. The anterior lobe is supplied by a low-pressure portal system, so severe hypotension can cause ischaemic necrosis. Loss of prolactin gives failure of lactation and loss of gonadotrophins gives amenorrhoea.

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 Endocrinology: pituitary vulnerability in pregnancy?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.