Which fetal monitoring test assesses fetal oxygenation and placental function during labor?

Which fetal monitoring test assesses fetal oxygenation and placental function during labor?

• A. Contraction stress test
• B. Non-stress test (NST) with continuous fetal heart rate monitoring
• C. Biophysical profile
• D. Umbilical artery Doppler

Answer: (B)

Fetal oxygenation and placental function are reflected in how the fetal heart responds to activity. The non-stress test uses continuous external fetal heart rate monitoring while the fetus is moving. When oxygen delivery is adequate and the fetal autonomic nervous system is functioning, the heart rate accelerates with movement, creating a reactive pattern. This indicates good oxygenation and placental support. During labor, this real-time monitoring provides immediate feedback on fetal well-being, so a reactive tracing supports continuing labor with reassuring placental function. If the tracing is nonreactive, it signals the need for further assessment of fetal oxygen reserves or placental reserve. In contrast, other tests have different focus: a contraction stress test intentionally induces contractions to see how the fetus tolerates a temporary drop in placental blood flow, with late decelerations suggesting potential placental insufficiency; a biophysical profile combines ultrasound measures with an NST to give a broader view of fetal well-being; umbilical artery Doppler looks at blood flow in the cord to assess placental perfusion directly. The NST provides a quick, real-time readout of how well the fetus is being oxygenated and supported by the placenta during labor.

Fetal oxygenation and placental function are reflected in how the fetal heart responds to activity. The non-stress test uses continuous external fetal heart rate monitoring while the fetus is moving. When oxygen delivery is adequate and the fetal autonomic nervous system is functioning, the heart rate accelerates with movement, creating a reactive pattern. This indicates good oxygenation and placental support. During labor, this real-time monitoring provides immediate feedback on fetal well-being, so a reactive tracing supports continuing labor with reassuring placental function. If the tracing is nonreactive, it signals the need for further assessment of fetal oxygen reserves or placental reserve.

In contrast, other tests have different focus: a contraction stress test intentionally induces contractions to see how the fetus tolerates a temporary drop in placental blood flow, with late decelerations suggesting potential placental insufficiency; a biophysical profile combines ultrasound measures with an NST to give a broader view of fetal well-being; umbilical artery Doppler looks at blood flow in the cord to assess placental perfusion directly. The NST provides a quick, real-time readout of how well the fetus is being oxygenated and supported by the placenta during labor.