Fetal monitoring during labour

摘要

Apparatus for monitoring fetal health during labour detects the occurrence of a fetal ECG in digital signals derived from electrodes on a fetus using a matched filter routine 36 to detect a QRS complex. The peaks of successive R waves are then found (operation 38) and used to determine fetal heart rate (operation 41). After time coherent filtering of digital samples representing the fetal ECG (operation 45) the P-R interval and the elevation of the S-T interval are found (operations 47 and 48) and a correlation coefficient between the fetal heart rate and the P-R interval is derived (operation 49). The elevation and the coefficient are displayed. If the correlation coefficient becomes positive for about half an hour and a significant fall in the elevation of the S-T interval also occurs it is an indication of acidosis of the fetus.