External physical stimulation of the human fetus during episodes of low heart rate variation.

The effect of shaking the fetus through the maternal abdomen during episodes of low (nonreactive) fetal heart rate variation was studied in 10 healthy nulliparous women near term. Heart rate monitoring from an abdominal electrocardiogram was combined with real-time scanning for body movements and fetal breathing. In each fetus two episodes of low variation were examined, one during which external stimulation was performed and one as a control without stimulation. There were no differences between the groups, with or without stimulation, in the duration of the nonreactive trace or heart rate variation or in the incidence of breathing or body movements. Therefore, shaking the fetus during a nonreactive heart rate episode has no useful purpose. The results are comprehensible in the light of fetal and neonatal behavioral states.