[Studies on the measurement of fetal breathing movement by the impedance method (author's transl)]

Fetal breathing movements (FBM) were detected without any invasion by recordings of impedance (IMP) variance on the maternal abdominal wall, where the FBM were visible through the myometrium and maternal abdominal wall. FBM was clearly shown by the IMP method in some modification. This IMP recordings consisted in several elements of maternal respiration and pulsation, fetal movements, FBM, etc. FBM elements on IMP recordings appeared to be in clear spike waves and these were identified as the FBM. Considering of the result of fetal respirotachogram utilizing of IMP recordings, FBM did not seemed to be regular movements. Fetal "hiccup' movements were shown as large biphasic spike waves on IMP recordings. FBM were accurately recognized by the separation of the FBM elements from FBM-IMP recordings by utilizing of the analogical subtractive amplifier system. FBM-IMP signals from the data recorder was dealt with the fast Fourier transformation (FFT) utilizing by the mini-computer system and frequency analysis of them was carried out. From the results of FFT passing through the infinite impulse response digital band-pass filter system, the only FBM elements were separately obtained.