Fetal monitoring: Identifying the relevant biosignals interdependencies

The interdependences between the maternal heart rate (mHR), the electrohysterogram (EHG) and the fetal heart rate (fHR) are of great interest, indicating the well developing of pregnancy, and they were initially analyzed in the current study by using the spectral coherence. The mHR and fHR were obtained by applying independent component analysis (ICA)and event-synchronous canceller (ESC) algorithms and considered together with the electrohysterogram (EHG) for analysis: their spectra and connectivity were evaluated within the multivariate analysis based on autoregressive model, its parameters being estimated by Kalman filter. The coherence analysis based on Fourier transform, the wavelet coherence and the partial directed coherence were then applied to obtain details about the influences among these signals and the directionality of their interdependences.