Early decelerations are periodic, gradual slowings of the fetal heartbeat, synchronized exactly with the contractions.

These dips are rarely more than 20 or 30 BPM below the baseline.

Importantly, these decelerations are gradual in onset and gradual in recovery and coincide exactly with the contraction.

These innocent changes are thought to be due, in many cases, to fetal head compression within the birth canal.

Sometimes, patients demonstrating early decelerations will later develop variable decelerations.