Calculator Inputs
Example Data Table
| Case | Beats | Seconds | Prev Baseline | Variability | Accelerations | Decelerations | Type | Contractions | Movements | Temp | Example Output |
|---|---|---|---|---|---|---|---|---|---|---|---|
| A | 38 | 15 | 148 | 10 | 2 | 0 | None | 2 | 7 | 36.9 | 152 bpm, reassuring |
| B | 44 | 15 | 158 | 4 | 0 | 2 | Variable | 4 | 3 | 37.8 | 176 bpm, borderline to high risk |
| C | 26 | 15 | 122 | 1 | 0 | 3 | Late | 6 | 1 | 38.2 | 104 bpm, urgent review suggested |
Formula Used
1) Current fetal heart rate: FHR = (Beats Counted ÷ Counting Seconds) × 60
2) Estimated baseline: If a prior baseline exists, Baseline = (Current FHR × 0.65) + (Previous Baseline × 0.35)
3) Trend change: Trend = Current FHR − Previous Baseline
4) Risk score: Weighted points are added for abnormal baseline, reduced or marked variability, decelerations, tachysystole, fever, low movement, and sharp trend shifts. Accelerations reduce the score.
5) Stability index: Stability Index = 100 − (Risk Score × 12), limited between 0 and 100
These rules create a structured screening summary. They are not a diagnostic replacement for a formal fetal monitoring interpretation.
How to Use This Calculator
- Count fetal heart beats during a known time window.
- Enter the number of beats and the exact seconds counted.
- Add previous baseline if you want trend comparison.
- Enter variability amplitude, accelerations, and decelerations.
- Select the dominant deceleration type, if present.
- Add contractions, observed movements, and maternal temperature.
- Press the calculate button to show the result above the form.
- Review the graph, summary table, CSV export, and PDF export.
FAQs
1) What does this calculator estimate?
It converts a counted heartbeat sample into beats per minute, then combines tracing features like variability, accelerations, decelerations, contractions, movement, and temperature into a structured review summary.
2) Is this a medical diagnosis tool?
No. It is an educational calculator for structured monitoring review. Clinical decisions should rely on trained interpretation, full fetal tracing context, direct examination, and emergency judgment when needed.
3) Why is counting time important?
The heart rate is calculated from beat count divided by seconds, then scaled to one minute. A wrong timing window can distort the result and shift the interpretation band.
4) What variability range is usually most reassuring?
Moderate variability is generally the most reassuring pattern in this calculator. Minimal, absent, or markedly excessive variability increases the score because those patterns usually need closer review.
5) Do accelerations always lower concern?
They often support a more reassuring picture, so this calculator reduces the score when accelerations are present. Still, overall interpretation depends on the full tracing and clinical context.
6) Why do contractions affect the result?
Frequent contractions can stress placental exchange and may worsen deceleration patterns. The calculator adds points when contraction frequency suggests tachysystole or increased monitoring pressure.
7) When should results be treated urgently?
Urgent patterns are flagged when baseline is strongly abnormal, variability is very poor, decelerations are repeated or severe, and other stress markers combine into a high review score.
8) What do the CSV and PDF downloads include?
The CSV file exports the calculated summary fields. The PDF captures the visible result block, including the interpretation, metric cards, result table, and the plotted fetal heart rate trend chart.