What it means
A healthy fetal heart rate does not run as a flat line; it wiggles around its baseline. Variability is graded by the size of these swings: absent (none seen), minimal (5 beats per minute or less), moderate (6 to 25 beats per minute) and marked (more than 25). Moderate variability shows that the baby's nervous system is getting enough oxygen; minimal or absent variability can come from sleep, some drugs or a lack of oxygen.
For the nurse
Describe variability every time you document the tracing. Report minimal or absent variability, especially with late decelerations; a fetal sleep cycle usually lasts no more than 40 minutes.
At a glance
| Also written | FHR variability, baseline variability |
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Related terms
uterine contraction
A tightening and then relaxing of the muscle of the uterus (womb), as happens during labor.
early deceleration
A gradual dip in the fetal heart rate that starts, bottoms out and ends at the same times as a uterine contraction.