An embryo has a defensive layer around it (zona pellucida) in the beginning of development. The procedure of implantation of the embryo starts on the fifth or sixth day after fertilization, when the embryo leaves its protective shell, zona pellucida vanishes and the embryo cell get into direct contact with the uterine coating cells. This additionally causes disposal of a mechanical barrier which would hinder further development of the embryo.
Issues with repetitive implantation failure may be caused by the embryo’s incapability to disrupt its protective shell or by the adjustments in the protective layer. In such cases, we perform assisted hatching. In this strategy,we upset the hard shell of the embryo by laser or by an extraordinary needle, just before the exchange. Therefore we make it moreeasier for it to append to the uterine wall.