The electrical activities of the uterus during pregnancy

In contrast to the current state of knowledge of cardiac and of gastrointestinal electrophysiology, our current knowledge of the physiology of the uterus during pregnancy is still very rudimentary. Despite seminal work performed in the past decades, there are still significant areas that we know little about. In this review, some of these areas are explored. For example, although many studies have tried to find the site of the uterus pacemaker, such a site has not yet been found and its mechanism and location remain, to date, a mystery. Similarly, there is much confusion as to the mechanism of propagation of the electrical impulse. Although the existence of gap junctions, connecting neighboring myometrial cells to each other, have been known since 1977, alternative or additional mechanisms are being suggested such as the potential existence of a network of interstitial cells, similar to the one that is functioning in the gut, or the involvement of stretch receptors to synchronize activity and contraction. In recent years, high-resolution studies have been introduced enabling detailed analysis of the location and spatial patterns of propagation. This work is being developed at the in-vitro level in isolated tissues, in the whole organ and in several animal species. Most recently, a surge in new technology enabling high fidelity and high resolution recording from the human uterus through the abdominal wall are being explored which could ultimately lead to new diagnostic tools and a clearer understanding of the physiology of pregnancies and (premature) labor.