Abstract: Decidualization is a delicate and complex process, which is regulated by hormones and cellular and molecular signals. Progesterone plays a leading role in the process of decidualization and embryo implantation. In the late period of menstrual cycle (the day 24-28 of menstrual cycle), the progesterone combined with progesterone receptor (PR) stimulates the synthesis of prolactin (PRL), a marker of endometrium decidualization, and mediates the occurrence of decidualization. In the complex mechanism of decidualization, progesterone and PR are mainly to control the epithelial cell proliferation to obtain uterine receptivity, and to stimulate stromal cell differentiation to establish pregnancy. The monitoring of progesterone and progesterone receptor has a guiding significance for the prediction of early embryo loss in those patients with habitual abortion. The role of progesterone and PR and the mechanism in decidualization were reviewed in this paper.

Key words:  Progestins；, Receptors, progesterone；, Endometrium；, Decidua；, Decidualization