Results
The overall design of the uterine contraction monitoring tool consists
of receiving signals, amplifying, filtering and sending them to
smartphone applications. Below the block diagram, show this process
(Figure 6) in which a signal will amplify after receiving from the body.
Then, through suitable filters, the target signal is extracted and
de-noised. Finally, data was extracted from an analog-to-digital
converter and sent via Bluetooth.
The developed device is portable, has a low weight, and can detect
uterine contractions without interfering with noise (Figure 7). The
usability of the device is easy, so that three electrodes receive
signals from the body. While sending signals, the LED, besides the
Bluetooth icon, is flashing light. After analysis, contraction signals
show on the smartphone. The battery of the device is chargeable and
located behind the device.
Sample contraction signals received from the device are shown in Figure
8. For device tuning, applying devices by pregnant women is needed.
Table 1 shows the results of the device evaluation. Two criteria for the
accuracy (RE) and repeatability (CV) of the device are calculated. The
numbers in the table showed that they were acceptable.
The smartphone application was developed in several sections (Figure 9).
It consists of a login section, a profile section includes age,
pregnancy age in weeks, number of deliveries, and type of delivery
includes cesarean or vaginal delivery in a previous pregnancy. Previous
uterine contraction tests, start new session and help. Abnormal
contractions are identified using strength, duration and frequency of
contractions, but this is the difference between women with or without
history of cesarean delivery. For preterm patterns, the application
shows warning notifications to users.