decidualização

Decidualization is a crucial process in mammalian reproduction where the endometrium, the lining of the uterus, is transformed into a decidua. This transformation is essential for successful implantation and the maintenance of pregnancy. Following ovulation, the corpus luteum produces progesterone, which primes the endometrium. In the presence of a pregnancy, embryonic signals, such as human chorionic gonadotropin (hCG) produced by the early embryo, further stimulate this process.

The decidual cells are specialized endometrial stromal cells that enlarge and accumulate glycogen and lipids. These cells are no longer identical to the original stromal cells and play a vital role in supporting the developing embryo. The decidua is not just a passive recipient of the embryo; it actively participates in pregnancy. It provides nutrients to the early embryo before the placenta is fully functional and plays a role in immune tolerance, preventing the maternal immune system from rejecting the semi-allogeneic embryo.

Furthermore, the decidua forms the maternal component of the placenta, contributing to the development of the maternal-fetal interface. This specialized tissue is critical for regulating exchange of nutrients, gases, and waste products between mother and fetus. The decidualization process is tightly regulated by hormonal signals, primarily progesterone, and various growth factors and cytokines. Disruptions in decidualization can lead to implantation failure, recurrent miscarriage, and other pregnancy complications. The decidua undergoes significant changes throughout pregnancy and is ultimately shed after childbirth during the postpartum period.