A low-cost pressure sensor for maternal uterine activity monitoring

In this paper we presented a novel pressure sensor that is highly suitable for assessing the variation of uterine activity to prevent preterm labor of high-risk women. The rate of preterm labor is increasing in modern societies and it results in huge medical expenditures. However, preterm labor is hard to perceive in advance because the sensitivity and significance of self-examine is low. The home uterine activity monitoring (HUAM) is a new methodology, which automatically sense the uterine activity and then send the information to physicians or practitioners for further advising or medication. The HUAM can effectively prevent the preterm labor but the conventional pressure sensors are uncomfortable and expensive. Our new design is based on a Colpitts self-oscillating circuit and a ferrite coil. It senses the pressure of uterine contraction by the coil displacement, which changes the output frequency. The proposed pressure sensor is light-weighted stable, low-cost, and is appropriate for portable and long-term applications of uterine monitoring.