Development Of Fetal Movement Monitor Based On Three Electrocardiogram Electrodes

The family and society pay high attention to the fetal health.Effective fetus monitoring is an important premise for the improvement of fetal health and early treatment.Fetal movement is a crucial indicator of fetal monitoring and fetal intrauterine health status.Counting the number of fetal movement by the perception of pregnant women themselves is a common method for the long-term monitoring of fetal movement.However,this method has a lot of defects.It cannot meet the accurate requirements of modern perinatal medicine.With the rapid development of bio-electronic technology,some progress has been made by medical sensors.However,it has not been used in fetal movement monitoring successfully.Because of this background,we developed a novel fetal movement monitor based on ECG electrode.The signals were firstly collected by three electrodes.Then,they were amplified and filtered.Later,the signals were sampled and processed with the microprocessor STM32 and were stored into the High Capacity SD card(To reduce electromagnetic radiation,we did not use wireless transmission technology,such as Bluetooth,WiFi).Last,the datain the SD card were read and analyzed by the computer.This study is mainly about the design of the monitor(both hardware and software)and its performance test.The specific contents are as follows.(1)Development of fetal movement monitor.Hardware aspects:ECG electrode array consists of three electrodes.They are attached on the above navel(2 ~ 3cm),the navel,and the below navel(2 ~ 3cm)of the pregnant woman.The electrodes were connected to the preamplifiers with electrode wires.After amplification of the preamplifier,the signal passed through 50 HZ non-pass filter and band-pass filter.The band-pass filter is composed of a second-order low-pass filter and a second-order high-pass filter.After amplified by two programmable amplifiers(PGA116),the signal,which was sampled and processed with the microprocessor STM32,was stored into the SD card.Software aspect: First,the programmable devices must be controlled work as the requirements.Then,the signal was collected into the register by setting a suitable sampling frequency.Last,the signal was stored into the SD card after the data processing.(2)Instrument performance test.The signal generator and the oscilloscope were used to test each module of the instrument separately.Then,the whole performance of the instrument was tested.Finally,the data of four pregnant women were collected and compared with the number counted by the pregnant women themselves.