What happens in implantation window?
Embryo–endometrial dialogue has led to the identification of a ‘window of implantation’. The implantation window is characterised by changes to the endometrium cells, which aid in the absorption of the uterine fluid. These changes bring the blastocyst nearer to the endometrium and immobilise it. The first step of implantation is the formation of foetal–maternal interface. Next crucial step is invasion of the embryo into the endometrium.
How implantation is mediated?
Implantation is initiated when the blastocyst comes into contact with the uterine wall. Certain molecules and pinopodes are involved in bringing embryo and endometrium together and attachment in embryo implantation. The embryo produces cytokines and growth factors and receptors for endometrial signals.
Does body immunity play role in successful pregnancy?
The embryo, as a genetic product of both maternal and paternal chromosomal material, can be seen as an allograft to the uterus. The body immune system plays an important role in implantation process. The host (mother)genetically different from the transplants(foetus), raises the possibility of a graft-versus-host reaction. The immunological action against the embryo can be described as maternal restraint.