Relationship of intrauterine fetal activity to maternal sleep stage

Abstract

An attempt was made to evaluate the possibility of a humoral, rather than neural, mediation of the epiphenomena of REM sleep. The exclusively systemic communication between a mother and her fetus provided a readily available preparation for an initial approach to this problem. With reference to the sleep of newborn infants, it was assumed that periods of active motility in the fetus of a sleeping mother reflected the occurrence of REM sleep in this organism. Maternal sleep was monitored by standard recording procedures, and fetal sleep was inferred from recordings of intrauterine activity. The following results were obtained from comparisons of all-night sleep records of the mother-fetus unit: (a) The fetus tends to develop a recurrent quiet-active cycle in the course of gestation. (b) Specific instances of high fetal activity frequently occur together with or in close proximity to the recurrent episodes of REM sleep in the mother. Such increases, when they occur, appear to be related to the appearance of maternal REM sleep; however, they are not a systematic feature of this sleep phase. (c) A number of potential mechanisms for a dynamic humoral communication between the two physiological units during REM sleep are discussed.