A comparative study of the fetal electrocardiogram recorded by the STAN an Nottingham systems.

Objective: To compare the T:QRS ratio recorded by the STAN and Nottingham fetal electrocardiogram (FECG) monitors.

Design: Prospective observational study.

Setting: London teaching hospital delivery suite and research unit.

Methods And Subjects: The T:QRS ratios generated by the STAN and Nottingham FECG monitors were simultaneously recorded and compared using signals generated from a computer-produced ECG signal and signals from 11 term fetuses recorded during labour.

Results: There was an acceptable level of agreement between the two systems with the computer-generated signals, but it was not clinically acceptable with the signals from the fetuses recorded during labour. Disagreements in the T:QRS values were probably due to differences in the reference points for the measurement of the S-T segment and T-wave height.

Conclusion: The different points of reference for measurement of S-T segment and T-wave height can explain poor agreement between the two methods of FECG waveform analysis. The suggested adopted points of reference are those corresponding to adult electrocardiographic methodology.