Assisted hatching consists of opening a hole in the embryo, specifically in the zona pellucida. In this way, the embryo is helped to break the zona pellucida, facilitating its implantation.
The external layer that surrounds the oocyte is the zona pellucida. The sperm crosses this layer when fertilization takes place and persists during the first days of development. With the passage of hours, this zone becomes thinner until it is finally broken by the embryo and in this way it can adhere to the endometrium.
The hole can be made mechanically (laser), chemically, through the use of Tyrodes acid.
Medical studies show that there is no evidence that implantation or live birth rates are improved with the use of Assisted Hatching, so the use of this technique is generally not recommended in infertile patients.