Reproduction: onset of lactation: 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 · Reproduction: onset of lactation

Sample item

Prolactin is high through pregnancy, yet copious milk secretion begins only after delivery. What permits lactation to start?

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

The answer and the reasoning

B. The fall in oestrogen and progesterone after delivery of the placenta removes their block on prolactin action

During pregnancy high oestrogen and progesterone prime the breast but prevent prolactin from fully stimulating milk synthesis. After the placenta is delivered these steroids fall abruptly, and prolactin can then drive copious milk production.

Option by option

  • A. A rise in FSH that stimulates mammary glands

    FSH acts on the ovary and has no direct role in starting milk secretion.

  • B. The fall in oestrogen and progesterone after delivery of the placenta removes their block on prolactin action (correct)

    Correct. Falling placental steroids release the block on prolactin action.

  • C. Release of oxytocin that stimulates prolactin synthesis

    Oxytocin causes milk ejection and does not drive prolactin synthesis for lactogenesis.

  • D. A surge in human placental lactogen after delivery

    Human placental lactogen disappears with the placenta and does not surge after delivery.

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 Physiology question

What is the answer to this Physiology question?

The best answer is B, The fall in oestrogen and progesterone after delivery of the placenta removes their block on prolactin action. During pregnancy high oestrogen and progesterone prime the breast but prevent prolactin from fully stimulating milk synthesis.

Why is "A rise in FSH that stimulates mammary glands" not the answer?

FSH acts on the ovary and has no direct role in starting milk secretion.

Why is "Release of oxytocin that stimulates prolactin synthesis" not the answer?

Oxytocin causes milk ejection and does not drive prolactin synthesis for lactogenesis.

Why is "A surge in human placental lactogen after delivery" not the answer?

Human placental lactogen disappears with the placenta and does not surge after delivery.

What concept does this question test?

It tests Reproduction: onset of lactation in Physiology. After the placenta is delivered these steroids fall abruptly, and prolactin can then drive copious milk production.

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 Reproduction: onset of lactation?

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.