ObGyn Intelligence
Built by Amos Grünebaum, MD Professor of Obstetrics & Gynecology · Maternal-Fetal Medicine · 50+ years on Labor & Delivery
Good fetal heart rate interpretation shouldn't depend on who happens to be at the bedside at 3 a.m. This tool gives every nurse, resident, midwife, and attending the same evidence-based framework — instantly. Free. Share it with your team.
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First in Clinical Medicine
The First Clinical Application of Navigational AI in Fetal Heart Rate Interpretation
Unlike conventional AI tools that pattern-match against training data or generate free-text responses, navigational AI follows the clinician's real-time inputs step by step — applying evidence-based rules at each branch to deliver a specific, actionable recommendation. The way an expert colleague thinks through a strip at the bedside. Not retrieval. Not summarization. Guided clinical reasoning.
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Intrapartum CTG Navigator

Intrapartum CTG Navigator

Cardiotocography: simultaneous assessment of fetal heart rate and uterine activity

ACOG · FIGO · NICE NG229 · NICHD

1
CTG Baseline
2
Variability & Accels
3
Decelerations
4
Uterine Activity
5
Clinical Context
✓
Recommendation
Step 1 — CTG Baseline Fetal Heart Rate
Mean FHR over a minimum 2-minute window, in the absence of accelerations and decelerations. Normal: 110–160 bpm (ACOG/NICHD [2]); 110–160 bpm (FIGO [3]); 110–160 bpm (NICE NG229 [4], with amber flag at 100–109 bpm)
Baseline FHR Required
bpm
Bradycardia: <110 bpm  ·  Normal: 110–160 bpm  ·  Tachycardia: >160 bpm
Please enter a value between 60 and 200 bpm
Baseline trend over the monitoring period Required
Please select one
Step 2 — Variability & Accelerations
Variability = amplitude of minor oscillations around the baseline. FIGO normal: 5–25 bpm [3]. NICE NG229: assess over 1-minute segments between contractions [4].
Baseline variability Required
Please select one
Accelerations Required
Please select one
Step 3 — Decelerations
Select all types present on the current CTG tracing. Decelerations are repetitive when associated with >50% of contractions (FIGO 2015 [3]).
Multiple types may be selected
Deceleration type(s) Select all present
Please make a selection
Step 4 — Uterine Activity
Uterine contractions are the second component of the CTG. Assessed over a 10-minute window. Normal: ≤5 contractions/10 min (ACOG/NICHD [2], FIGO [3], NICE NG229 [4]).
Contraction frequency Required
Please select one
Contraction duration Required
Please select one
Uterine resting tone Required
Please select one
Oxytocin / uterotonic currently infusing? Required
Please select one
Step 5 — Clinical Context
All three guideline systems (ACOG, FIGO, NICE) emphasize that CTG must be interpreted in the context of clinical risk factors, not in isolation.
Stage of labor Required
Please select one
Gestational age Required
Please select one
Clinical risk factors Select all that apply
FIGO, NICE, and ACOG all require risk factor integration into CTG interpretation
Source Publications

This tool integrates four major international guideline systems and one key evidence publication. Every classification, threshold, and management recommendation is traceable to one of these sources. Where guidelines differ, the tool applies the most conservative clinically actionable standard and notes the discrepancy.

1
ACOG Practice Bulletin No. 106: Intrapartum Fetal Heart Rate Monitoring: Nomenclature, Interpretation, and General Management Principles. Obstet Gynecol. 2009;114(1):192–202.
doi:10.1097/AOG.0b013e3181aef106
ACOGThree-tier systemOxytocin management
Establishes the NICHD three-tier classification (Category I = normal, II = indeterminate, III = abnormal) and the management framework applied by this tool. Defines intrauterine resuscitation measures, amnioinfusion indications, and the principle that Category III requires immediate evaluation with possible expedited delivery. Category II is the most clinically challenging tier, encompassing a wide spectrum of tracings that cannot reliably predict fetal acid-base status.
2
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: Update on Definitions, Interpretation, and Research Guidelines. Obstet Gynecol. 2008;112(3):661–666.
doi:10.1097/AOG.0b013e3181841395
NICHDCTG definitions
The consensus foundation for all NICHD-based CTG terminology used in this tool: baseline rate (normal 110–160 bpm), variability categories (absent / minimal / moderate / marked), acceleration thresholds (≥15 bpm × ≥15 sec at term; ≥10 × 10 before 32 weeks), deceleration types (early, variable, late, prolonged, sinusoidal), and normal uterine activity (≤5 contractions per 10 minutes). These standardized definitions are applied verbatim in the input options.
3
Ayres-de-Campos D, Spong CY, Chandraharan E; for the FIGO Intrapartum Fetal Monitoring Expert Consensus Panel. FIGO consensus guidelines on intrapartum fetal monitoring: Cardiotocography. Int J Gynaecol Obstet. 2015;131(1):13–24.
doi:10.1016/j.ijgo.2015.06.020
FIGO 2015Normal / Suspicious / Pathological
The international FIGO consensus guideline, developed with 44 experts from 14 countries, uses a three-class system (Normal / Suspicious / Pathological) distinct from the ACOG/NICHD Category I/II/III tier naming. FIGO definitions: normal variability 5–25 bpm; reduced variability <5 bpm for >50 minutes in baseline or >3 minutes during decelerations. Decelerations are repetitive when associated with >50% of contractions. Accelerations denote fetal non-hypoxia; their absence during labor is of uncertain significance. Suspicious tracings require corrective measures and close surveillance; pathological tracings require rapid corrective action and — if no improvement — expedited delivery. This guideline is the basis for the comparative classification table in this tool.
4
National Institute for Health and Care Excellence. Fetal monitoring in labour. NICE Guideline [NG229]. London: NICE; December 2022. Available from: https://www.nice.org.uk/guidance/ng229
NICE NG229 2022Normal / Suspicious / PathologicalUterine contractions included
The most recently updated major CTG guideline (December 2022). Key update from prior NICE guidance: uterine contractions are now formally included as a fourth CTG feature in the classification — previously only three features (baseline, variability, decelerations) were classified. CTG features are categorized as white (normal/reassuring), amber (non-reassuring), or red (abnormal). A tracing is: Normal if all features are white; Suspicious if any one feature is amber; Pathological if any one feature is red, or two or more features are amber. NICE adds sepsis, meconium, and slow progress as explicit risk modifiers requiring lower threshold for action. Prolonged deceleration ≥3 minutes: prepare for possible immediate delivery.
5
Simpson KR, James DC. Effects of oxytocin-induced uterine hyperstimulation during labor on fetal oxygen status and fetal heart rate patterns. Am J Obstet Gynecol. 2008;199(1):34.e1–34.e5.
doi:10.1016/j.ajog.2007.12.015
Oxytocin thresholds
Provides the physiological evidence basis for oxytocin cessation thresholds. Demonstrates that uterine hyperstimulation — tachysystole with FHR changes — is associated with measurable fetal oxygen desaturation on fetal pulse oximetry. The severity-stratified oxytocin decision (STOP vs. REDUCE vs. MAINTAIN) applied by this tool maps to this paper's findings. Supports the clinical principle that oxytocin cessation — not merely dose reduction — is required when tachysystole coincides with abnormal CTG features.
6
Skupski DW, Rosenberg CR, Eglinton GS. Intrapartum fetal stimulation tests: a meta-analysis. Obstet Gynecol. 2002;99(1):129–134.
doi:10.1016/s0029-7844(01)01648-3
Fetal stimulation
Meta-analysis of intrapartum fetal stimulation (scalp stimulation and vibroacoustic stimulation). An acceleration response meeting threshold criteria (≥15 bpm × ≥15 sec) is associated with fetal scalp pH >7.19: sensitivity 68%, specificity 96%. The tool recommends stimulation when accelerations are absent or variability is reduced in non-Category-III tracings, citing these performance characteristics. Absence of acceleration response does not confirm acidosis — clinical escalation is required.
Three-System Classification Comparison

The three major guideline systems use different tier names but closely aligned criteria. This tool cross-references all three in the result output. Key differences are highlighted below.

CTG Feature ACOG/NICHD [1,2] FIGO 2015 [3] NICE NG229 2022 [4]
TIER NAMES Category I / Category II / Category III Normal / Suspicious / Pathological Normal / Suspicious / Pathological
BASELINE NORMAL 110–160 bpm 110–160 bpm 110–160 bpm (100–109: amber)
VARIABILITY NORMAL Moderate: 6–25 bpm 5–25 bpm bandwidth 5–25 bpm (NICE measures over 1-min segments)
REDUCED VARIABILITY (concerning) Minimal: >0–5 bpm (Category II) <5 bpm for >50 min, or >3 min in decel (Suspicious) <5 bpm = amber feature; absent = red feature
LATE DECELERATIONS Recurrent = Category II or III (depending on variability) Repetitive = Suspicious; with reduced variability = Pathological Red feature = Pathological
VARIABLE DECELERATIONS Recurrent, uncomplicated = Category II; with absent variability = Category III Uncomplicated = Normal/Suspicious; complicated features = Pathological Uncomplicated = amber; complicated or prolonged = red
SINUSOIDAL PATTERN Category III Pathological Pathological (red feature)
UTERINE CONTRACTIONS Assessed separately; tachysystole >5/10 min Assessed separately; tachysystole >5/10 min Included as 4th CTG feature in classification (2022 update)
PROLONGED DECEL ≥3 MIN Category II/III — urgent evaluation Pathological — rapid action Prepare for immediate delivery — urgent obstetrician + senior midwife
SEPSIS AS MODIFIER Mentioned as risk factor Listed as risk factor for pathological interpretation Explicitly flagged — lower threshold for expedited delivery; fetal scalp stimulation inappropriate in sepsis (NICE 2022)

Key Differences Between Guideline Systems

Tier namingACOG/NICHD uses Category I/II/III. FIGO and NICE use Normal/Suspicious/Pathological. Broadly equivalent tiers, but NICE 2022 has finer granularity with white/amber/red feature coding within the Suspicious tier.
ContractionsNICE NG229 (2022) is the only major guideline to formally include uterine contractions as a fourth classification feature — not just an adjunct assessment. This tool reflects that distinction.
Prolonged decelNICE sets the most specific action threshold: a single prolonged deceleration ≥3 minutes triggers immediate preparation for delivery and urgent obstetric review. FIGO and ACOG require ≥2 minutes for the prolonged category but set less prescriptive thresholds.
SepsisNICE NG229 uniquely specifies that fetal scalp stimulation is inappropriate in the presence of suspected sepsis or chorioamnionitis (inflammatory pathway to brain injury differs from hypoxic pathway). This tool reflects that exception.
Scalp pH / FBSFIGO and NICE include fetal blood sampling (scalp pH and lactate) in their management algorithms for Suspicious/Pathological tracings. ACOG removed FBS from routine US practice. This tool focuses on bedside CTG management rather than FBS protocols.
Oxytocin Decision Framework

How this tool determines oxytocin management, based on Simpson & James [5] and ACOG PB 106 [1], cross-referenced with FIGO [3] and NICE NG229 [4] conservative measures guidance.

CTG CategoryUterine ActivityRecommendationEvidence
Normal / Cat INormalMaintainNo evidence of fetal compromise. Continue standard titration. [1]
Suspicious / Cat IINormalReduce ≥50%Indeterminate tracing warrants conservative dose reduction pending reassessment. [1,3]
Suspicious / Cat IITachysystoleStopTachysystole + abnormal CTG = fetal oxygen desaturation. Simpson & James [5].
Suspicious / Cat IIHyperstimulation or late/prolonged decelsStopCessation + resuscitative measures. Consider tocolysis if no improvement. [1,3,4]
Pathological / Cat IIIAnyStop immediatelyFirst resuscitative step. ACOG, FIGO, and NICE all specify cessation in abnormal tracings. [1,3,4]
Scope & Limitations
⚠This tool applies published NICHD/ACOG/FIGO/NICE criteria. It does not access the full clinical picture — maternal vitals, complete tracing history, fetal position, cervical exam, or comorbidities.
⚠Category II / Suspicious encompasses a wide clinical spectrum. The framework is conservative by design. Clinical judgment and trajectory assessment must modulate all recommendations.
⚠Fetal stimulation sensitivity and specificity values (68% / 96%) are from meta-analysis [6]; performance varies with gestational age, sedation, and fetal sleep state.
⚠NICE NG229 notes that CTG has a high false-positive rate and limited evidence to support its use in low-risk labor. Continuous CTG is recommended for high-risk pregnancies and specified clinical situations.
⚠FIGO (2015) notes that suspicious and pathological tracings have limited capacity to predict metabolic acidosis — large percentages of such tracings do not result in acidosis. CTG is sensitive but has low specificity and low positive predictive value for acidosis [3].
⚠In any rapidly evolving or deteriorating situation: do not wait for this tool. Call for help, perform immediate bedside assessment, and act on clinical judgment.