Which of the following indicates a reactive Non-Stress Test (NST)?

Which of the following indicates a reactive Non-Stress Test (NST)?

• A. FHR accelerations of 10 bpm for 10 seconds
• B. FHR accelerations of 15 bpm lasting at least 15 seconds
• C. No fetal movements detected
• D. Two fetal movements and no accelerations

Answer: (B)

A reactive Non-Stress Test (NST) is characterized by specific criteria involving the fetal heart rate (FHR) and its responses to fetal movements. The criteria that define a reactive NST typically include fetal heart rate accelerations that meet certain thresholds. The correct answer reflects the standard definition of a reactive NST: FHR accelerations of 15 beats per minute (bpm) lasting at least 15 seconds. This indicates that the fetus is experiencing adequate oxygenation and is responsive to stimuli, which is a reassuring sign of fetal well-being. The acceleration in heart rate during periods of fetal movement demonstrates the autonomic nervous system's functioning properly and suggests that the fetus is not under stress. In contrast, a scenario where FHR accelerations are defined as only 10 bpm for 10 seconds does not meet the criteria for reactivity, as it is below the commonly accepted thresholds. Additionally, the absence of fetal movements or having two fetal movements without any heart rate accelerations indicates that the fetus may not be responding adequately, which does not fulfill the reactive NST criteria. Therefore, only the description of FHR accelerations of 15 bpm for at least 15 seconds aligns with the definition of a reactive NST.

A reactive Non-Stress Test (NST) is characterized by specific criteria involving the fetal heart rate (FHR) and its responses to fetal movements. The criteria that define a reactive NST typically include fetal heart rate accelerations that meet certain thresholds.

The correct answer reflects the standard definition of a reactive NST: FHR accelerations of 15 beats per minute (bpm) lasting at least 15 seconds. This indicates that the fetus is experiencing adequate oxygenation and is responsive to stimuli, which is a reassuring sign of fetal well-being. The acceleration in heart rate during periods of fetal movement demonstrates the autonomic nervous system's functioning properly and suggests that the fetus is not under stress.

In contrast, a scenario where FHR accelerations are defined as only 10 bpm for 10 seconds does not meet the criteria for reactivity, as it is below the commonly accepted thresholds. Additionally, the absence of fetal movements or having two fetal movements without any heart rate accelerations indicates that the fetus may not be responding adequately, which does not fulfill the reactive NST criteria. Therefore, only the description of FHR accelerations of 15 bpm for at least 15 seconds aligns with the definition of a reactive NST.