What does "fetal heart rate reactivity" refer to?

Fetal heart rate reactivity specifically refers to the presence of two or more fetal heart rate accelerations within a defined time frame, typically 20 minutes. This reactivity is an important indicator of the fetal well-being and neurological function, as it suggests that the fetus is responding appropriately to stimuli, indicating good oxygenation and overall health.

Accelerations are characterized by transient increases in the heart rate of at least 15 beats per minute above the baseline and lasting for at least 15 seconds. When these accelerations are observed, it is indicative of a healthy autonomic nervous system and adequate fetal conditions.

The other options do not accurately describe reactivity. The absence of changes in fetal heart rate would indicate a non-reactive tracing, which can signal potential issues with fetal oxygenation or health. A consistent baseline heart rate without changes suggests stability but does not satisfy the criteria for reactivity. Lastly, a focus solely on deceleration patterns overlooks the essential aspect of acceleration, which is fundamental to defining reactivity. Thus, the presence of two or more accelerations during a monitoring period is what characterizes fetal heart rate reactivity.