Development of fetal heart monitoring system

Nonstress test (NST) is the widely used measurement technique to monitor fetal well-being from 32 weeks pregnant. One of the key components is an acoustic probe, which measures the heart rate of a fetus. The movement of a mother and the fetus results in the misalignment of the acoustic beam and degrades the reliability of the measurement. This work presents the Doppler-signal based motion tracking system to compensate for the movement of the target. The probe is made of multiple ultrasound transducers, which interface with a Doppler-signal converter. After scanning the location of the fetus inside the uterus, the probe tracks the fetus by using a 2-degree-of-freedom (DOF) mechanical tracking system. This work will present the characteristics of two key components: acoustic and electrical performance of the multi-channel Doppler transducers and the algorithm of the 2-DOF tracking system. The proposed system can decrease signal loss during the NST and improve the overall reliability of the fetal well-being test. In the long term, it can reduce the burden of skilled medical assistance in the NST, and potentially can be one of a key component of telemedicine.