Parametric spectral analysis of umbilical artery Doppler signals for fetal heart rate variability evaluation.

To improve the measurement resolution of the fetalheartrate (FHR) beat-to-beat variation, which is an important prognostic indicator of fetal well-being. Method: The goal was reached using an autoregressive (AR) approach, instead of conventional algorithms based on the Fast Fourier Transform (FFT), for the analysis of the umbilicalarteryDopplersignals. Results: The resolution improvement obtainable with the proposed technique in the FHR beat-to-beat variation was proved both with simulation and with experimental results. The method was implemented in a personal computer (PC) based equipment which works in a quasi-real time mode. Conclusions: The proposed technique can be usefully applied to the FHR beat-to-beat variation measurements; the developed prototype is at present used for clinical practice at the 'Clinica Ostetrica e Ginecologica' of the University of Firenze