Electronic fetal monitoring does not measure oxygen — it measures the fetal autonomic response to it. Drive the four features that make up an interpretation and the cardiotocograph on the right redraws itself, then tells you which of the three categories the tracing has just earned and why. Then name the mechanism behind each deceleration shape, and sort the causes of a flat strip into the ones you watch and the ones you escalate.
Set the four features
140 bpm
Mean rate over a 10-minute window rounded to the nearest 5 bpm, excluding accelerations, decelerations and stretches of marked variability, with at least 2 minutes of identifiable baseline. Normal is 110–160 bpm.
Variability reflects an intact pathway from cerebral cortex through midbrain to vagus nerve to the fetal heart — so it reports on the fetal brain, not just the fetal heart.
3 · Deceleration patternNone
The strip is a teaching drawing generated from the four features you set, not a recording of a real fetus. Roughly 10 minutes of paper is shown with three contractions.
Tracing
The shape and the timing are on the right. Two words do the work: gradual (30 seconds or longer from onset to nadir) means a reflex or chemoreceptor pathway; abrupt (less than 30 seconds) means the cord is being squeezed.
Mechanisms named0 / 0
The variability has gone flat. Each finding below either explains it benignly or tells you the fetal central nervous system is running out of oxygen. Sort all eight.
Sorted correctly0 / 0
Category IBaseline 110–160, moderate variability, no late or variable decelerations