Counting fetal movements of small-for-gestational infants using a fetal movement acceleration measurement recorder

Background: Our purpose was to clarify whether small-for-gestational (SGA) infants is associated with a decrease in fetal movements (FMs) even in the absence of hypoxia. We used a fetal movement acceleration measurement (FMAM) recorder, which enabled counting gross FMs for hours at a time.Methods: (1) Parameters of FMs for 13 women who delivered SGA infants were plotted over normal reference value curves made from 64 normal pregnant women in another study. (2) Linear regression analysis was conducted for the women with SGA infants and the normal pregnant women.Results: Thirty-eight data recordings were available in the SGA group. (1) For the ratio of movement positive 10-s epoch, 14 recordings (36.8%) were below 10% of the normal values. For an average number of movements, 13 (34.2%) were below 10%. Regarding average number, average duration, and longest duration of non-movement period, 12 (31.6%), 13 (34.2%), and 15 records (39.4%) were above 90% of the normal values, respectively. (2) SGA was a factor that decreased the positive epoch ratio and the average movements number, and increased the average number and duration, and the longest duration of non-movement period.Conclusions: SGA is associated with decreased movements even in the absence of hypoxia.