Human Fetal Behavioral State at Term

Abstract

The present study was designed to test the existence of behavioral states in the fetus at term using simplified techniques. For this purpose simultaneous recording of the fetal heart activity by means of phonocardiotocography and of fetal body movements by means of real-time ultrasound was performed by using a multichannel recorded. The fetal heart activity was analyzed for two parameters: (1) long-term variability and (2) baseline accelerations. The fetal body movements were classified into three types. 880 min of recording time from 50 fetuses at 37–41 weeks of gestation were analyzed. Each segment of 1 and 3 min was classified into four distinct states, according to the combination of the above parameters. The segments that failed to fit into one of these states were labeled as ‘no state’. The frequency of each parameter was also independently calculated. The results were statistically analyzed by using a computer. The significance of the difference between the observed frequencies of the various states and their expected frequencies (obtained by the frequencies of the individual parameters) was calculated by the Χ² test. Behavioral states of a duration of 3 min were observed in 45.6% of the total periods recorded which is significantly higher (p < 0.001) than the 4.1% expected.

Fetal Habituation to Sound Stimulus in Various Behavioral States

“…Fetal movments were classified, in addi tion to 'no movement', into three types: startle, simple and trunk rotation. Four behavioral states were determined using these vari ables in a method described elsewhere (table 1) [12], Habituation to sound stimulus was defined as the ceasing of fetal startle response to 5 consecutive stimuli.…”