Assisted hatching (AHA or “assisted hatching”) is a technique of embryo micromanipulation used from late 1980s and consists of making a hole in the pellucid zone to favour the embryo ‘hatches’ out, allowing it to implant in the uterus.
We know that once the embryo reaches the blastocyst stage, its pellucid zone breaks to continue dividing the embryo. But there are cases in which the pellucid zone becomes very hard after fertilization and cannot be broken, making it impossible for the embryo to reach the blastocyst stage, consequently there is no implantation, the embryo dies and there is no pregnancy.
This technique is recommended for patients with problems in the oocyte pellucid zoneThat is, for patients that, after classic IVF or ICSI, can obtain good quality embryos and adequate endometrium.
Assisted hatching is also recommended for embryos after defrosting as the embryo freezing process significantly hardens the wrapped egg (pellucid zone).
Before the embryo transfer, a small hole in the pellucid zone egg is opened via using a laser beam; this will facilitate the subsequent exit of the embryo in blastocyst state and its latter implantation in the uterus.