Fetal Heart Rate Calculator: Baseline & NICHD Categories

Check a fetal heart rate against the usual 110-160 bpm range and see which category it falls in. Educational tool, not a medical diagnosis.

Quick 1-Click Fetal Heart Rate Presets

Clinical Monitoring Inputs

Normal: 110–160 bpm
12 to 42 completed weeks
Moderate: 6–25 bpm
Auscultation device
Baseline Heart Rate
140bpm
Normal range: 110–160 bpm
Gestational Age
28weeks
3rd Trimester
Cardiac Beat Interval
429ms
Interval between beats
NICHD Classification
Category I
Reassuring baseline

20-Minute Illustrative Monitoring Timeline

110–160 bpm Target Band

Green shaded band highlights normal baseline range. Fluctuations show simulated beat-to-beat variability.

NICHD Category Interpretation

Clinical Classification:
Normal / Reassuring - Strongly predictive of normal fetal acid-base equilibrium.
Baseline Rate140 bpm
Variability Amplitude10 bpm (Moderate / Healthy)
Crucial Health Disclaimer: This calculator is an educational reference only. If you notice reduced or altered fetal movement patterns, immediately contact your maternity assessment unit or midwife.

Worked Example: Baseline Interpretation for 140 bpm at 30 Weeks vs 105 bpm

How clinical guidelines categorize baseline fetal heart rate patterns:

Case A: Routine Checkup
30 weeks gestation | Baseline: 140 bpm | Category I
Case B: Borderline Low
36 weeks gestation | Baseline: 105 bpm | Category II
Case C: Severe Bradycardia
39 weeks gestation | Baseline: 95 bpm | Category III
Standard Normal Range
110 to 160 beats per minute (bpm)
Clinical Guideline Evaluation:
•1. Case A (140 bpm): Lies squarely within the 110–160 bpm normal range. Classified as Category I (Normal / Reassuring). Indicates physiological fetal acid-base equilibrium.
•2. Case B (105 bpm): Falls below 110 bpm but remains above 100 bpm. Classified as Category II (Indeterminate / Equivocal). Requires continued monitoring, maternal position change, and hydration.
•3. Case C (95 bpm): Below 100 bpm. Classified as Category III (Abnormal / High Risk). Mandates immediate clinical obstetric intervention and resuscitation.
•4. Beat-to-Beat Interval: At 140 bpm, the interval between consecutive cardiac cycles is 60,000 / 140 = 428.6 ms.

💡 Obstetric Takeaway: A baseline of 140 bpm is reassuring. Clinical diagnosis always incorporates accelerations, variability, and contraction patterns during formal cardiotocography (CTG).

Frequently Asked Questions

Authoritative Obstetric & Fetal Health Guidelines

ACOG Practice Bulletin No. 106 - Intrapartum Fetal Heart Rate Monitoring

Official American College of Obstetricians and Gynecologists clinical practice guidelines for nomenclature and fetal interpretation.

NICHD - Report on the 2008 National Institute of Child Health Workshop

Standardized definitions for baseline fetal heart rate, Category I/II/III classification, variability, and decelerations.

RCOG - The Use of Electronic Fetal Monitoring (Green-top Guideline)

Royal College of Obstetricians and Gynaecologists guidelines on intrapartum CTG monitoring and home Doppler warnings.

NHS - Monitoring Your Baby's Heartbeat in Pregnancy

Patient guidance on fetal movements, antenatal appointments, and when to seek urgent maternity assessment.

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