Table 6.

Sensors’ description of the above-mentioned papers.

Ref	Sensors	Description
[7]	Accelerometer, clinical-grade thermometer, and pulse oximetry module	An accelerometer sensor measures the acceleration of anybody or an object [49]. A thermometer is used to measure and display body temperature [50]. A pulse oximeter is used to monitor the amount of oxygen carried in the body [51].
[24]	Commercial IMU	Shimmer 3 from Shimmer Sensing (accelerometers and gyroscopes) [38]
[20]	EPS Sensor	It is a feedback-enhanced and stabilized electrometer-based amplifier that operates based on current displacement measurements.
[21]	Toco Sensor	Measures the tension of the maternal abdominal wall [52].
[22]	AgCl electrode	It has good conductivity, low noise, and a stable baseline.
[23]	PPG sensor	An uncomplicated and inexpensive multi-point measurement method that is often used for heart rate monitoring purposes [53].
[25]	Multi-point IMU	Used to measure acceleration, angular velocity, and magnetic fields [54].
[26]	Two mCube MC3672 accelerometers	Ultra-low-power, low-noise, integrated digital output 3-axis accelerometers with a feature set optimized for wearable [55].
[27]	Tri-axial accelerometer	Provides simultaneous measurements in three orthogonal directions [56].
[4]	Accelerometer, gyroscope, and temperature	An accelerometer sensor measures the acceleration of anybody or an object. A gyroscope senses angular velocity [49,57].
[28]	Garmin vívosmart 2 smart bands	The device monitors heart rate at the wrist and includes helpful tools such as all-day stress tracking [58].