Labour and delivery: pethidine and the newborn: 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 · Labour and delivery: pethidine and the newborn

Sample item

A woman received 100 mg of intramuscular pethidine 90 minutes before delivery. The newborn has a normal heart rate but is limp with poor respiratory effort. Which effect is the most likely cause?

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

The answer and the reasoning

B. Opioid respiratory depression

Pethidine and its metabolite norpethidine cross the placenta and depress the neonatal respiratory centre, with peak effect when delivery occurs 1 to 3 hours after a dose. The baby needs ventilatory support until the drug effect wears off.

Option by option

  • A. Early-onset neonatal sepsis

    Sepsis would present with temperature instability and a toxic picture rather than this isolated post-opioid picture.

  • B. Opioid respiratory depression (correct)

    Correct. Placental transfer of the opioid depresses the newborn's respiratory drive.

  • C. Congenital diaphragmatic hernia

    A diaphragmatic hernia gives respiratory distress with a scaphoid abdomen, not a limp baby with poor effort.

  • D. Neonatal hypoglycaemia

    Hypoglycaemia causes jitteriness and seizures, not isolated apnoea after a recent opioid.

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 OBG questions

Questions about this OBG question

What is the answer to this OBG question?

The best answer is B, Opioid respiratory depression. Pethidine and its metabolite norpethidine cross the placenta and depress the neonatal respiratory centre, with peak effect when delivery occurs 1 to 3 hours after a dose.

Why is "Early-onset neonatal sepsis" not the answer?

Sepsis would present with temperature instability and a toxic picture rather than this isolated post-opioid picture.

Why is "Congenital diaphragmatic hernia" not the answer?

A diaphragmatic hernia gives respiratory distress with a scaphoid abdomen, not a limp baby with poor effort.

Why is "Neonatal hypoglycaemia" not the answer?

Hypoglycaemia causes jitteriness and seizures, not isolated apnoea after a recent opioid.

What concept does this question test?

It tests Labour and delivery: pethidine and the newborn in OBG. The baby needs ventilatory support until the drug effect wears off.

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 Labour and delivery: pethidine and the newborn?

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.