Fetal Heart Monitor for Prenatal Telemedical Applications

Despite the rise in telecommunication systems and advances in medicine over the last 30 years, telemedical adaptations for prenatal appointments have not experienced similar growth. Pregnant mothers must undergo routine in-clinic examinations to monitor the well-being of the fetus. While many such in-clinic exams were already an inconvenience to mothers, the social distancing requirements of COVID-19 revealed a need for both the reduction in frequency and duration of in-person visits. This project presents a remote fetal heart monitoring system that can be used in the comfort and safety of the patient’s home. With a handheld doppler, a pregnant mother can acquire their baby’s heartbeat signal independently. The signal can be transmitted to a computer for processing and visualization on our intuitive user interface. Voltage readings from the doppler device are communicated to a computer through an embedded Bluetooth microcontroller and a corresponding receiver. A bandpass filter and autocorrelation techniques convert the voltage readings to a discrete heartrate every second, which is graphed on the user interface’s fetal heart rate (BPM) vs. time (min.) plot. The patient can then send an image of the plot to their provider through an established mode of communication for further analysis. The final device was tested against a Fitbit, during resting and active conditions, to evaluate accuracy of measurements. Values were compared using a student’s t-test to observe if there was a significant difference between heartrates collected by the Fetal Heart Monitor and a Fitbit, under multiple conditions. Though this device may not completely omit the need of in-person prenatal visits, it takes an important step in the direction of developing telemedical care for pregnant women.