NICHD fetal heart rate category (I, II, III)
Sorts a fetal heart rate tracing into the NICHD three-tier system.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Baseline fetal heart rate
- 140 beats per minute
- Baseline variability
- Minimal (detectable, 5 beats per minute or fewer)
- Late decelerations
- Recurrent, with half or more of the contractions
- Variable decelerations
- Absent
- Sinusoidal pattern
- Absent
Result: Category II, because minimal variability is not absent variability
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Category I
- All of: baseline 110 to 160 beats per minute, moderate variability, late decelerations absent, variable decelerations absent.
- Category II
- Every tracing that is neither Category I nor Category III.
- Category III
- Absent variability with recurrent late decelerations, recurrent variable decelerations or bradycardia; or a sinusoidal pattern.
- Minimal is not absent
- Category III needs absent variability. Minimal variability with recurrent late decelerations is Category II.
- Category II is a residual
- Not a middle severity. It covers an enormous range, most tracings fall in it, and it calls for evaluation and continued surveillance.
- What it is not
- A point-in-time description, not a prediction. None of the three categories is a management algorithm.
What you enter
- Baseline fetal heart rate
- Baseline variability
- Late decelerations
- Variable decelerations
- Sinusoidal pattern (Category III on its own)
How this is calculated
Macones GA, Hankins GDV, Spong CY, Hauth J, Moore T. The 2008 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring. Obstet Gynecol. 2008;112(3):661-666. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.
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