Fetal ECG Extraction from Abdominal ECG Using Chebyshev and Butterworth Filters

Fetal electrocardiography (FECG) is the electrical activity of the fetal heart muscles to reveal important information about its status. However, such a recording of the FECG is usually not beneficial as it is mostly overwhelmed by the maternal ECG (MECG) and other sources of noise. This paper proposes a combination of signals from three electrodes measuring Abdominal ECG (AECG) signals to cancel the maternal peaks. Four different FECG extraction methods that rely on using Chebyshev and Butterworth filters were used to extract the FECG signal from the combined signal. Method 1 utilized Chebyshev Type 1 low-pass and high-pass filters, while Method 2 utilized Butterworth low-pass and high-pass filters to perform the extraction. On the other hand, Methods 3 and 4 used bandpass Chebyshev Type 1 and Butterworth filters, respectively. Method 1 showed the best performance and was able to successfully capture the FECG features and allowed finding the heart rate of the fetus, which was ~132 bpm. The proposed signal can be potentially used in other applications to extract bio-signals.