Assisted hatching, a scientific technique used in In Vitro Fertilisation (IVF), may improve the implantation of embryos into a woman’s uterine lining by creating an opening through which the embryonic cells can hatch out. Pregnancy cannot occur unless the embryo hatches.
Just before embryo implantation, the developing embryo must “hatch” out of its outer shell (zona pellucida). Some embryos seem to have a thicker shell that may decrease their ability to hatch and therefore reduce the likelihood that they will implant. This may be due to the age of the woman or other, unknown reasons.
The early embryo consists of a ball of cells surrounded by a protective outer shell called the zona pellucida. In order to implant into the lining of the uterus the embryo needs to break out of this shell by a process called ‘hatching’.
It has been suggested that in some cases failure to reach pregnancy may be caused by the embryo being unable to break out of the zona pellucida to complete this process. The technique of Assisted Hatching aims to facilitate the hatching process by creating a small hole in the zona pellucida on day 3 by which, a few days later, the subsequent blastocyst will be able to hatch out of the shell.