What is the stage of implantation?

Migration and hatching

The migration of the zygote and the trophoblast are the first and second migration steps, respectively, that take place during implantation.[14] The fallopian tube’s ampulla is where the oocyte is fertilized. The zygote is propelled towards the uterus by cilia on the tube’s lining.

The zygote goes through several cell divisions during this migration, resulting in the formation of a morula, a ball of 16 compressed blastomeres. After three or four days, the morula penetrates the uterus, and as it does so, a cavity known as the blastocoel is created in the morula to develop the blastocyst.

Apposition

The first loose link or contact between the blastocyst and the endometrium after zona hatching is referred to as apposition. A tiny crypt in the endometrium and enough zona pellucida breakdown to allow the blastocyst trophoblast to come into direct touch with the underlying endometrium are the two conditions that typically lead to apposition.

Adhesion

Compared to free apposition, adhesion is a significantly more powerful attachment to the endometrium.

Through the endometrium’s penetration and trophoblast cell protrusions, the trophoblasts adhere.

The microvilli on the trophoblast are what are doing the adhering. This adhesion process is aided by the trophoblast’s binding fiber connections, laminin, collagen type IV, and integrins.

Invasion

The blastocyst’s continued establishment within the endometrium is known as invasion. Gelatinase A and B are used to continue the proliferation and penetration of the trophoblast cell protrusions into the endometrium. Trophoblasts enter the uterus in an effort to draw blood from the mother in order to lay the groundwork for fetal blood flow.