Read the strip both ways. Name the feature, then see how the US Category system and mechanism-based physiology disagree about the same tracing.
Cardiotocography is a dual signal: the uterine contraction that stresses placental perfusion, and the fetal heart rate that adapts to it. This drill trains you to read both — and to feel the gap between the two dominant interpretive frameworks.
Five modules · master 7 of your last 10 to unlock the next
Uterine signal — tachysystole, resting tone, relaxation interval, prolonged contraction. The half the US guideline leaves largely undefined.
Fetal heart rate — baseline, variability, and the four deceleration types (NICHD).
US Category I / II / III — the three-tier pattern-recognition system, including the Category II catch-all.
Global physiologic state — no hypoxia, compensation, decompensation, and the named hypoxia types.
The dyad contrast — one strip, two verdicts, with oxytocin- and misoprostol-driven tachysystole front and center.
Strips start as clean schematics, then become realistic noisy tracings as you advance within each module.
Choose your clock
Seconds allowed per item. Your choice applies for the whole session — the mode and a live countdown stay at the top of the screen while you play.
What this drill is built on
Teaching tool only. It does not interpret real patient tracings and does not replace clinical judgment or your unit's protocol. Strips are generated illustrations of defined patterns.
Before you start
Two languages, one strip
The same tracing gets read two ways. Before drilling the features, get the vocabulary straight.
A cardiotocograph carries two channels — the uterine contraction and the fetal heart rate. The US and global traditions read those channels with different words, and they don't even agree on what the object of surveillance is.
One 10-minute strip · FHR (navy) over uterine activity (purple)
Both frameworks read these two channels. They differ in what they call them — and in which channel is the point.
US / ACOG
Global · FIGO + physiological
The recording
Fetal heart rate monitoring — a single signal
Cardiotocography — a dual signal (cardio + toco)
What is being watched
The fetal heart rate
The maternal–fetal unit
Naming the overall trace
Category I / II / III
Normal / suspicious / pathological (FIGO), or no hypoxia / compensation / decompensation (physiological)
Uterine activity is defined as
Tachysystole only
Contraction morphology, duration, resting tone, relaxation interval, and tachysystole
How a trace is read
By recognizing patterns
By linking uterine cause to fetal response
That is the vocabulary. What these differences actually do — at the bedside, and to the same strip — is what the five modules are for. The last one puts both verdicts side by side.
Mapping per Grünebaum, Dudenhausen, Chervenak. Int J Gynecol Obstet 2026 (Tables 1–2) · FIGO 2015 · ACOG CPG No. 10 (2025) · Intl Expert Consensus on Physiological CTG (2024).
Module map
Urgent · 10sModuleStreak 0Last 10 0/0Score 0
10
FHR (bpm) · uterine activity
—
Module cleared
Evidence base
Every definition, threshold, and category in this drill traces to one of these sources. Nothing is invented.
RefVerify note. The FIGO 2015 Cardiotocography consensus carries DOI 10.1016/j.ijgo.2015.06.020. This drill follows the NICHD 2008 / ACOG 2025 definitions for US nomenclature and the 2024 International Expert Consensus for mechanism-based physiologic interpretation. Where two frameworks define the same feature differently, the drill shows the divergence rather than reconciling it — which is the point of the parent paper.
About this drill
Labor physiology is a dyad. The uterine contraction intermittently throttles intervillous perfusion; the fetus responds with cardiovascular and oxygenation adaptations. Read in isolation, a fetal heart rate pattern loses the cause that produced it.
Two frameworks, one strip
Global cardiotocography guidance (FIGO, NICE, the international physiological consensus) keeps both signals in view. It defines contraction morphology, duration, resting tone, and the relaxation interval, treats the maternal–fetal unit as the object of surveillance, and intervenes on abnormal uterine activity before the fetus deteriorates — a preventive posture.
The US framework (ACOG Clinical Practice Guideline No. 10, 2025) defines tachysystole but leaves most uterine physiologic parameters unspecified, and triggers intervention chiefly when fetal heart rate abnormalities are present. The result is a comparatively reactive, fetal-centric model in which the Category II tier becomes a large, heterogeneous catch-all.
Why the contrast matters
Induction and augmentation are rising, and uterotonics can drive excessive uterine activity. Oxytocin can be paused or titrated; once misoprostol is given, it cannot be removed — only tocolysis and supportive measures remain. When the relaxation interval and resting tone are not defined, the early, uterine-driven signal of hypoxic stress is the part most easily missed. That is the case the final module is built around.
How to use it
Drill the feature classes in order. Strips begin schematic and become realistic. Mastery is accuracy under mild time pressure — 7 correct of your last 10. The feedback after each item names the physiology and the source, so the drill teaches reasoning, not just labels.
Structured collaboration. Built in the ObGyn Intelligence vibe-coding model: the evidence is sourced and verified first; the clinician decides what teaches; the tool renders it. The LLM drafts; the clinician executes.
