Author(s): Maeda K
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Abstract Fetal movement has been recorded by marking maternal perception, observation of real-time B-mode or ultrasonic M-mode with conventional techniques. Continuous and objective recording of fetal movement is studied with the application of the ultrasonic Doppler method in the present paper. Continuous wave ultrasound Doppler probe of a fetal monitor is utilized, and a very low frequency Doppler signal of 8 Hz or more is introduced into a band pass filter with a band of 20 to 80 Hz. The output is changed into a spike-shaped signal, and recorded on the uterine contraction channel of the monitor. Vibrating steel ball movement with a velocity of 0.77 to 3.1cm/sec was recorded in the water bath experiment. The detecting area was as narrow as 8mm in diameter, but linearity was clear in the range of movement from 2.5 to 5.5mm. A clinical study showed simultaneous occurrence of bursts of spiky fetal movement signals and FHR acceleration in the late stages of pregnancy. Fetal movement did not accompany this acceleration in the cases of 18 and 21 weeks of pregnancy. Very regular hiccup-like fetal movement with 25 to 28 cpm frequency was recorded in 2 cases of late stage gestation. The fetal hiccup did not accompany the acceleration. Fetal resting and active phases will be differentiated by the new recording technique.
This article was published in Nihon Sanka Fujinka Gakkai Zasshi
and referenced in Journal of Health & Medical Informatics