Decidual reaction

The decidual reaction is the set of changes in the endometrium of the uterus that prepare it for implantation of an embryo. These changes are observed in each menstrual cycle and enhanced after implantation. These changes include swelling of stromal cells due to accumulation of glycogen and other nutrients. These nutrients help the embryo survive the initial days before the placenta is fully developed, which then establishes a channel for fetus nutrient exchange.