Various Techniques for Fetal ECG Signal Monitoring

The paper present a various techniques that enables the investigations of the fetal heart rate (FHR) fluctuations. Later, the common problems associated with these techniques are discussed with some solutions. A non-invasive technique is also proposed for fetal ECG monitoring. The proposed system will be designed to measure the fetal heart rate variability for the evaluation of autonomic nervous system (ANS) and to investigate its development as a function of the gestational age and body mass index (BMI). This will be a real time new method to assess instantaneous fetal heart rate variation (beat to beat) during gestation period with automated analysis of FHR variability using Doppler ultrasound method. The method will consists of three steps: Doppler envelope filter, variable threshold detector and non retriggerable monostable multivibrator having adjustable pulse width for heartbeats detection. The performance parameters will be i) coefficient of variance (CVRR) as an index of parasympathetic activity, and ii) a low frequency/high frequency (LF/HF) ratio as a sympathetic activity. The R–R interval variability will show the variation between consecutive heart beats, change over time was eventually adopted to calculate for timedomain, frequency domain analysis. In the frequency domain analysis power spectral density (PSD) of the RR series will be calculated by analyzing powers and peak frequencies of different frequency bands. Index Terms –Fetal ECG, Ultrasound, FHR, ANS, BMI. ________________________________________________*****______________________________________________