Uterine peristaltic activity and the development of endometriosis.

Peristaltic activity of the nonpregnant uterus serves fundamental functions in the early process of reproduction, such as directed transport of spermatozoa into the tube ipsilateral to the dominant follicle, high fundal implantation of the embryo, and, possibly, retrograde menstruation. Hyperperistalsis of the uterus is significantly associated with the development of endometriosis and adenomyosis. In women with hyperperistalsis, fragments of basal endometrium are detached during menstruation and transported into the peritoneal cavity.