Real time fetal ECG monitoring based on a personal computer using correlation technique

The authors present a real-time technique for detecting the fetal electrocardiogram from abdominal recordings. An averaged maternal waveform is obtained by using a cross-correlation function, which is then subtracted from the abdominal signal, resulting in complete elimination of the maternal signal. The fetal heart rate and an averaged fetal ECG (electrocardiogram) is then extracted by using the same averaging process, making it possible to recognize fetal P and T waves. The recording system is based on an IBM AT compatible personal computer with an 80286 processor and 80287 coprocessor. Since computer performances were not sufficient to give real-time outputs, a fast correlator board was developed which works in parallel with the computer and is able to enhance the computer throughput. The system is simple, and no special training is required.