A Wireless and Wearable System for Fetal Heart Rate Monitoring

Fetal heart rate monitoring can effectively reflect the health-status of the fetus, and provide an important basis for the diagnosis of fetal diseases. Prenatal and postnatal care also can be guided from continuous and accurate fetal heart rate monitoring. However, limited by many problems (e.g., cumbersome equipment, complex operation, movement interference), the available fetal heart monitoring systems are not convenient for long-term continuous monitoring anytime and anywhere. In this paper, a flexible wearable wireless fetal ECG (fECG) monitoring system is developed. Five flexible electrode patches are used to form multiple measurement channels and interference elimination channels, and the singular value decomposition algorithm is combined to improve the measurement accuracy. Based on the micromachining technology and the laminated packaging technology, a multi-unit integrated structure of electrode, transmission line and processing circuit is designed, and the flexible structure of serpentine wire is constructed to realize the ductility of the whole device. The signal acquisition device is only 12.5g weight and the thickness of the electrode patch is only 0.25mm. The device can be perfectly conformal to skin, greatly improving the wearing comfort. The data can be transmitted wirelessly through Bluetooth, enabling portable measurement anytime and anywhere. The results of clinical application show that the system can accurately detect fetal heart rate, maternal heart rate and uterine contractions, and the results are in good agreement with those of commercial Philips fetal monitor. The system can continuously monitor fetal heart rate for more than 6 hours and provide strong guarantee for fetal health monitoring.