[A study of sleep-waking rhythms based on pattern-recognition of continuous fetal heart rate monitoring].

Two different rhythms exist in the fetal heart rate (FHR) pattern of a full-term fetus. These rhythms seem to be related to the rhythms associated with sleep and wakefulness, but the results are not yet conclusive. In this study, at first, the states of sleep and wakefulness in newborn infants (measured simultaneously by EEG, EOG, respiration and body movement) were compared with their heart rate patterns in rest, active, awake and unclassified phases. The results suggest that in newborn infants it is possible to distinguish quiet sleep from other states of sleep and wakefulness by means of the heart rate pattern alone. In the second part of the study, NST for three consecutive hours with 24 to 41 week pregnant women was performed and examined to determine the relationship between maturity and heart rate pattern (measured minute by minute in rest, active and unclassified phases) in their fetus. The findings suggest that the rest phase in a heart rate pattern of a fetus indicates the fetus to be in a state of quiet sleep. Further, the proportional increase and significant increase in the duration of the rest phase after 34 gestational week indicate the maturity of the central nervous system of the fetus.