Prostaglandins and the myometrium and cervix.

Prostaglandins have long been thought to play important roles in the mechanism of parturition. Here we review the involvement of prostaglandins in myometrial and cervical functions with emphasis on human labor and birth. In addition, the cellular sources of prostaglandins as well as their interactions with various other endocrine, paracrine and physical factors, such as oxytocin, corticotropin releasing hormone, nitric oxide, platelet activating factor, cytokines, endothelin and stretch are also addressed together with their potential role in the molecular reorganization of cervical structure associated with labor and delivery. Finally, the premier role of progesterone in pregnancy maintenance and parturition is juxtaposed with the proposed "fine-tuning", modulatory role of prostaglandins and the above listed factors in the regulation of parturition.