Fetal movements associated with fetal heart rate accelerations and decelerations.

In normal pregnant women, the relationship between the FHR and fetal movements (FM) was evaluated during 1,541 consecutive observed FM of at least 1 second's duration. Two observed FHR changes were: (1) accelerations and (2) accelerations followed by decelerations. An acceleration in FHR was observed in association with 91.2 per cent of all FM of 1 to 3 seconds' duration and with 99.8 per cent of FM of longer than 3 seconds' duration. FM were associated with an acceleration followed by a deceleration 66.7 per cent of the time. FM lasting longer than 1 second and associated with neither accelerations nor decelerations were seen 1.8 per cent of the time.