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BackgroundA newly developed fetal movement acceleration measurement recorder has made it possible to count gross movements for hours. The purpose of this study was to determine the normal reference values for such movements.MethodsOne hundred and six pregnant women recorded fetal movements by themselves when they slept at home weekly from 28 weeks to term. The normal reference values were determined based on the data that could be recorded for more than 4 h per night.ResultsA total of 2,458 h of data from 385 recordings from 64 women was available. The median ratio of 10-s periods in which fetal movements occurred to the total time interval was 17% at 28 gestational weeks, decreasing to ∼6% at term. The number of fetal movements was 74 times/h, decreasing to 29 times at term. The number, the mean, and the longest durations of periods with no fetal movement, meaning no fetal movements were found for more than 5 min, were 1.56 times/h, 7.95 and 14.25 min, respectively, at 28 weeks, and increasing to 2.54 times, and 9.63 and 19.67 min, respectively, at term.ConclusionsThis study provides normal reference values for gross fetal movement count using the fetal movement acceleration measurement recorder.

A real-time rapid eye movement (REM) sleep detection system has been developed, which is composed of a portable digital recorder and a personal computer (PC) connected with a USB interface. The recorder amplifies, filters and samples the polygraphic signals such as electromyogram (EMG), electrooculogram (EOG), and electroencephalogram (EEG), and then sends them to the PC. The PC enables the real-time detection of REM sleep by heuristically evaluating the EMG activities, number of rapid eye movements, and the power spectral density of the EEG for every 10 s epoch. The performance of the developed system has been assessed by comparing the scores with those of off-line processing.