Establishing a reference value for the frequency of fetal movements using modified 'count to 10' method

To establish a reference value for the frequency of fetal movements perceived by the mother during the second half of pregnancy.

The study subjects consisted of 705 low risk Japanese pregnant women who continuously received antenatal care. We asked women to record the time required to perceive 10 fetal movements ('count to 10' time) everyday. We asked women to record it, not at a fixed time (i.e. evening time), but whenever they felt the fetus move the most actively. The position during counting (i.e. sitting position) was also not specified, and thus we named this method as modified 'count to 10' method. Satisfactory recordings were obtained from 690 women, which we used for analysis.

The 'count to 10' time was almost the same from 22 weeks (10.9; 7.3-18.0 (median; interquartile range)) until 32 weeks (10.0; 6.2-15.6), and it Thirty-two weeks showed the shortest time, which gradually increased toward 40 weeks (14.8; 9.5-24.0). Its 90th percentile was approximately 25 and 35 min at 22-36 weeks and at 37-40 weeks, respectively.

For the first time we established a reference value for perceived fetal movements throughout the second half of pregnancy. The present modified 'count to 10' method requires less time than the previous method. Approximately 98% (690/705) of women gave us satisfactory recordings. This reference value may be of use in identifying mothers with decreased fetal movements.