variability
The fluctuation in fetal heart rate baseline over time, indicating fetal neurologic integrity and oxygenation status.
Full Definition
Fetal heart rate variability refers to the irregular fluctuations in the baseline fetal heart rate that occur over both short-term (beat-to-beat) and long-term (cycles per minute) intervals. Variability is classified as absent (undetectable), minimal (≤5 beats per minute), moderate (6-25 beats per minute), or marked (>25 beats per minute). Moderate variability indicates intact fetal neurologic pathways and adequate oxygenation, while decreased or absent variability may suggest fetal hypoxemia, acidosis, or central nervous system depression from medications or congenital anomalies. Assessment of variability is a cornerstone of fetal heart rate interpretation during antepartum and intrapartum monitoring.
Usage
Usage note: Specify the degree of variability (absent, minimal, moderate, marked) in clinical documentation. Do not use as a standalone term without qualification.
In Context
- "The fetal heart rate tracing shows moderate variability with appropriate accelerations." — Fetal monitoring interpretation
- "Decreased variability was noted following maternal administration of meperidine for labor pain." — Labor and delivery note