Duration, amplitude and shape of accelerations in relation to fetal body movements in behavioral state 2F.

The relationship between fetal movements and fetal heart rate accelerations was analyzed in 34 healthy near term fetuses. Periods of coincidence 2F (C2F) with a mean duration of 34 +/- 6 minutes per fetus were selected, with a total of 463 accelerations. Nineteen percent of single body movements and 71% of compilations of movements were accompanied by an acceleration. The minimal duration of single movements associated with accelerations was 4-5 seconds. Movements with associated accelerations differed significantly in duration from movements without accelerations. The duration of accelerations was strongly correlated with the duration of movements. The amplitude of accelerations was not clearly correlated with the duration of movements, but depended on the type of movement. The shape of accelerations appeared to be dependent on the timing of the various fetal movements. In 77%, the number of notches in the accelerations was equal to the number of pauses in the movement complications. A discrepancy between notches in accelerations and pauses in movements could be explained in the majority of cases when the timing of the various movements in relation to one another was considered, or by the presence of fetal mouth movements.