Feasibility of an anterior abdominal electrode array for non-invasive measurement of uterine contractions across the menstrual cycle

While traditionally associated with pregnancy and labor, uterine contractions (UC) also occur throughout the menstrual cycle. Abnormalities in UC frequency and/or direction throughout the cycle are correlated with many uterine disorders, which can have downstream impacts on overall health, necessitating continuous monitoring throughout the cycle. Current UC monitoring technologies are invasive or bulky, and not suitable for routine monitoring. The most promising approach uses non-invasive surface abdominal electrodes in a method known as electrohysterography (EHG). However, current EHG methods remain unsuitable for longitudinal monitoring due to bulkiness and reliance on patient-specific anatomical scans. Furthermore, there are no simulations of non-pregnant UC to aid in resolving these limitations. In this work, we evaluate the feasibility of EHG using an electrode array placed only on the anterior abdomen of size 6.35 x 14 cm and without any knowledge of patient anatomy for non-invasive measurement of UC across the menstrual cycle though both simulation and experiment. We identify a signal-to-noise ratio necessary to resolve frequency, amplitude, and direction of UC in simulation. In experimental data, all recordings met the coherence criterion identified in simulation, and we find patterns across the menstrual cycle which are congruent with previous literature. These results demonstrate the feasibility of an anterior abdominal electrode array for monitoring UC across the menstrual cycle, a step towards wearable EHG.