Progesterone regulation of cervix ripening in preterm and term birth.

Unlabelled: The cervix functions both as gatekeeper barrier to maintain pregnancy and virtually vanish for birth at term in mammals. The period of remodeling well-before term is characterized by an inflammatory process associated with reduced cell nuclei density and cross-linked collagen, as well as increased density of resident macrophages in cervix stroma. Contemporarily, progesterone (P4) is at or near peak concentrations in maternal circulation.