Apparatus and method for non-invasive, passive fetal heart monitoring
An apparatus and method for fetal heart and maternal heart and uterine monitoring is provided which acquire biopotential waveforms indicative of the mother's heart beat from sensors located at or near the mother's chest, and waveforms indicative of the combined maternal and fetal heart beats from abdominal sensors located on the mother's abdomen, lower back, or both. The signals from the abdominal sensors are divided into a plurality of channels. An adaptive signal processing filter (ASPF) algorithm or other suitable algorithm is then used to cancel the estimated maternal waveform from each channel derived from the abdominal sensors. The system then selects from the resulting waveforms at least one waveform to serve as the reference fetal waveform. The reference waveform is then processed against the other abdominal waveforms preferably using the ASPF algorithm again to form an enhanced fetal signal that is a representation of the fetus's biopotential electrocardiogram (EKGf). The EKGf can subsequently be used to measure fetal heart rate and other biophysical profile parameters. Surface electromyogram (EMG) signals allow for concurrent monitoring of uterine contractions and afford improved cancellation of motion artifacts.
The Johns Hopkins University
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Wayne I. Edward J. John A. Robert S.
Sternberger Moses Christion Greenberg