The formation of the decidua capsularis occurs after the process of implantation. Once the blastocyst implants into the uterine wall, the endometrial cells undergo a transformation called decidualization. This process includes the accumulation of glycogen, lipid droplets, and increased vascularization, which support the growth and development of the embryo. The decidua capsularis forms as the trophoblast cells of the blastocyst proliferate and envelop the developing embryo.
