Uterine contraction and physiological mechanisms of modulation.

Control of the smooth muscle in the uterus (the myometrium), is of vital importance during pregnancy and parturition. It is therefore understandable that several physiological mechanisms (neuronal, hormonal, metabolic, and mechanical) play a role in the control of myometrial activity. As our knowledge of the mechanism of uterine contraction has increased much in recent years, it is now possible to begin to explain, in some detail, how the contractile activity may be modulated. A detailed account of the mechanism of contraction in the uterus is therefore given, followed by examples of modulation of this process for each of the four physiological methods listed above. Examples have been chosen to illustrate either general or particular mechanisms of modulation. The goal of many working in this field is to understand these processes and thus prevent preterm labor and uterine dysfunction in term labor, which are still significant clinical problems.