A New Kind Of Monitor System For The Uterine Contraction

Derived from the electrical activity generated at the muscle fiber lever, uterine EMG provides complementary information on the muscle. During the last 60 years, uterine EMGs have been extensively investigated at the cell and tissue levels, at whole-organ myometrial and abdominal levels. EHG (Electrohysterogram) is the recording of uterine electromyogram with external electrodes located on the abdomen of pregnant woman. It provides complementary information on the muscle, and appears to be very promising techniques for clinical or physiologic investigations of uterine activity, compared with current invasive monitoring.However, until now, most of EHG study was based on only single-lead recordings. Since EHG signal has no fixed pace-making areas, single-lead recordings will lose phase information of uterine activity. Using unipolar electrode, the EHG signal is badly noised by many other signals (remaining of electrocardiogram, electromagnetic noise, electrode movement,…). A new kind of monitor system for the uterine contraction, therefore, is presented in this paper. The main problems involved in the development of a multi-channel EHG data-acquisition system are examined carefully and the respondent approaches to solve the problems are presented.To pick up multi-channel uterine EHGs exactly, a novel multi-channel biopotential amplifier is presented. The proposed circuit has many interesting characteristics regarding simplicity and cost, while achieving high CMRR and effective dc interference suppression without any trimming.The surface Laplacian involves the second derivative of the potential. It will give different and perhaps more localized information concerning the sources that give rise to the surface potential distribution. The surface Laplacian recordings can be obtained indirectly using a five electrodes array. In this article we put forward a new type of electrodes that is called active Laplacian electrode. It Integrates concentric rings electrode with bioelectricity preamplifier and is capable of acquiring localized information. We can local the EHG signals source more easily by using this new electrode.