Antenatal care: non-stress test: 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 · Antenatal care: non-stress test

Sample item

Which finding defines a reactive non-stress test?

ABaseline fetal heart rate of 100 bpm with absent variabilityBAt least two late decelerations in 20 minutesCNo accelerations in 40 minutesDAt least two accelerations of 15 bpm lasting 15 seconds in 20 minutes

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

The answer and the reasoning

D. At least two accelerations of 15 bpm lasting 15 seconds in 20 minutes

A reactive NST has a normal baseline (110 to 160 bpm), normal variability, and at least two accelerations of 15 bpm above baseline lasting 15 seconds within 20 minutes. Before 32 weeks the criterion is 10 bpm for 10 seconds. A reactive trace suggests an intact fetal autonomic system.

Option by option

A. Baseline fetal heart rate of 100 bpm with absent variability
Absent variability with bradycardia is non-reassuring.
B. At least two late decelerations in 20 minutes
Late decelerations are abnormal findings.
C. No accelerations in 40 minutes
No accelerations in 40 minutes is a non-reactive test.
D. At least two accelerations of 15 bpm lasting 15 seconds in 20 minutes (correct)
Correct. Two qualifying accelerations in 20 minutes define reactivity.

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 OBG question

What is the answer to this OBG question?

The best answer is D, At least two accelerations of 15 bpm lasting 15 seconds in 20 minutes. A reactive NST has a normal baseline (110 to 160 bpm), normal variability, and at least two accelerations of 15 bpm above baseline lasting 15 seconds within 20 minutes.

Why is "Baseline fetal heart rate of 100 bpm with absent variability" not the answer?

Absent variability with bradycardia is non-reassuring.

Why is "At least two late decelerations in 20 minutes" not the answer?

Late decelerations are abnormal findings.

Why is "No accelerations in 40 minutes" not the answer?

No accelerations in 40 minutes is a non-reactive test.

What concept does this question test?

It tests Antenatal care: non-stress test in OBG. Before 32 weeks the criterion is 10 bpm for 10 seconds. A reactive trace suggests an intact fetal autonomic system.

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 Antenatal care: non-stress test?

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.