A review of fetal ECG detection and enhancement methodologies

This paper presents a review of fetal electrocardiogram (FECG) detection and enhancement methodologies developed since 1960. The methods discussed include the subtraction, correlation, orthogonal basis, adaptive filtering and linear combination techniques. Subtraction is the oldest and most straightforward approach. It involves the direct subtraction of a near-thoracic maternal ECG from an abdominally-measured composite of maternal and fetal heart signals. Correlation is used for detection rather than enhancement. Other methods exist which make this technique obsolete. The most current methods for FECG detection and enhancement are the orthogonal basis, adaptive filtering and linear combination methods. These techniques were developed with the idea of producing a scheme which would allow greater flexibility in electrode positioning. An overview is given of the adaptive filter technique and the orthogonal basis methods. Finally, a method using a linear combination of electrodes to enhance FECG signals is discussed