Which test is used to evaluate fetal well-being by observing fetal heart rate in response to fetal movement over a period without contractions?

• A. Sonography
• B. Contraction stress test
• C. Biophysical profile
• D. Non-stress test (NST)

Answer: (D)

Monitoring fetal well-being by watching how the heart rate changes with the fetus’s own movements while there are no contractions is best done with a non-stress test. This test uses external sensors to record the fetal heart rate as the fetus moves spontaneously. A reactive result—typically two or more accelerations of the fetal heart rate of at least about 15 beats per minute above baseline, each lasting around 15 seconds within a 20-minute period—suggests good placental function and adequate oxygenation.

If the tracing doesn’t show enough accelerations, the test is considered nonreactive, and clinicians may try vibroacoustic stimulation or move on to other assessments like a biophysical profile or a contraction stress test to further evaluate fetal status. Other tests such as sonography or contractions-based stress testing assess different aspects: imaging with ultrasound or the fetal heart rate response to induced contractions, respectively.