Fetal Electrocardiogram Monitoring via an Intrauterine Catheter

Currently, the invasive scalp electrode has proved to be a reliable technique for monitoring fetal status via heart rate (HR) during delivery. However, the scalp electrode has various limitations. These limitations include an inability to obtain fetal electrophysiological information and little flexibility for placing a biosensor on the scalp electrode to monitor maternal contractions from the electromyogram (EMG). A fetal electrocardiogram (FECG) obtained via an intrauterine catheter electrode during delivery has potential to convey fetal HR and electrophysiological information. Furthermore, the intrauterine catheter can be modified to contain a pressure sensor to monitor maternal contractions. The modified catheter would enable fetal HR and electrophysiological information along with contractions to be monitored with one biosensor. Finally, this paper presents clinical data from the intrauterine catheter to determine the feasibility of obtaining a FECG from this approach. The clinical data obtained from the five patients studied indicates that after maternal electrocardiogram (EGG) cancellation, a FECG with a good signal-to-noise ratio can be obtained in an ECG diagnostic bandwidth of 0.05 to 100 Hz. From the diagnostic bandwidth, fetal HR and electrophysiological information can be determined.