The Movement Response of the Human Fetus to Sound Stimuli

N a preliminary report of their work on human fetal behavior, Sontag and Wallace described the muscular responses of the fetus to certain sound stimuli. Since the publication of that report, considerable progress has been made in the accumulation and interpretation of data on this subject. The results of these further experiments are presented here because we feel that they add something to the existing understanding of the physiology of the unborn child. While the phenomena of the response of the human fetus to sound stimuli has previously been reported by Forbes and Forbes (1), Peiper (2), Ray (3) and others, these reports are observations in the main, more or less occasional observations and are not suitable for statistical analysis. In no instance have these investigators attempted to determine the time of onset of this response; its reliability or its changes with increased fetal age.