Fetal movement counting at home with a fetal movement acceleration measurement recorder: A preliminary report

Objective: Fetal Movement Acceleration Measurement (FMAM) recorder was developed to facilitate gross fetal movement counting. The aim was to assess its reliability. Methods: Using the recorder, six pregnant women recorded fetal movements by themselves when they slept at their home weekly from 30 weeks to term. The recorder has 2 acceleration sensors; 1 for fetal movement (FM sensor) and another for maternal movement (MM sensor). Before sleeping, each subject attached the FM sensor to her abdomen, and the MM sensor to her thigh. All the recorded data were divided into 10-sec epochs, and presence of fetal movements was judged for all epochs (total epoch). The epoch was judged as positive for movement (positive epoch) when the FM sensor detected abdominal wall oscillations and the MM sensor did not detect maternal movements. The percentage of positive epoch number to total epoch and the maximum consecutive negative epoch number was calculated. Results: The mean percentage was approximately 20-25% at 30-34 weeks and 10-15% at 35-38 weeks. The negative epoch number linearly increased after approximately 33-34 weeks of gestation. Conclusions: The FMAM recorder was reliable for long-duration recording of gross fetal movements at home.