Reference values for a fetal movement acceleration measurement recorder to count fetal movements

Abstract

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.

Correlation between umbilical cord length and gross fetal movement as counted by a fetal movement acceleration measurement recorder

“…The FMAM recorder was described in detail in our past studies [12,13]. It weighs 290 g and can be used at home.…”

“…An epoch with any fetal movements was judged to be one positive epoch. The decision was made using a custom-made software system (Version 1.04 A, NoruPro Light Systems, Inc. Tokyo Japan), which was developed for the FMAM recorder [12,14]. The ratio of positive epochs to all epochs during one night was calculated as the movement index.…”

“…First, the correlation between the cord length and the movement index was examined. In a previous study, we reported that the movement index decreases as pregnancy progresses, with the decrease being relatively rapid around 32–35 weeks [12]. Therefore, the recordings were divided into three groups based on gestational weeks, i.e.…”

“…We have developed a fetal movement acceleration measurement recorder (FMAM recorder, http://e-mother.co-site,jp) that was designed for home use [11,12]. The recorder records gross fetal movements by detecting oscillations of the mother’s abdominal wall caused by fetal movements.…”

“…The agreements expressed by prevalence-adjusted bias-adjusted kappa were 0.82-0.83 which meant almost perfect values [11]. Furthermore, using the FMAM recorder, we recently made normal reference values for gross fetal movement counts and demonstrated that the values are similar to those made using ultrasonography [12]. The FMAM recorder has made it possible to count gross fetal movements over many hours.…”