Assisted hatching (AH) is an embryo micromanipulation technique that consists of making a hole in the envelope (zona pellucida) of the embryo to promote hatching and facilitate embryo implantation in the uterus. It is known that once the embryo reaches the blastocyst stage, its zona pellucida ruptures so as to enable embryo implantation. However there are cases in which the zona pellucida is abnormally hard, making it impossible for the embryo to get out by its proper means. Consequently, there is no implantation and the embryo dies.
This technique is recommended in patients with problems of the zona pellucida. This means, in patients where, after classic IVF or ICSI, good quality embryos and adequate endometrium are obtained but implantation fails. Assisted hatching is also recommended in embryos after freezing and thawing because these processes may notably harden the zona pellucida.
Before embryo transfer, a small hole is opened in the zona pellucida by means of the laser beam so as to facilitate the subsequent exit of the embryo in the blastocyst stage and implantation in the uterus.