Decidualization
（重定向自Decidualisation）
Decidualization is a characteristic of the endometrium of the pregnant uterus. It is a response of maternal cells to the hormone progesterone. Decidualization may be used to describe any change due to progesterone. These changes include the eosinophilic proliferation around arterioles after ovulation or progesterone action on endometrium which increases glandular epithelial secretion, stimulates glycogen accumulation in stromal cell cytoplasm, and promotes stromal vascularity (spiral arterioles) and edema. The sum of all the changes in the endometrium is significant, thus justifying a new term. The process is decidualization; the endometrium is now called decidua and it is ready for the implantation of the embryo.