Assisted hatching may be recommended for women who have failed IVF or for women over 35. During the initial stages of development, an embryo is contained in a layer of proteins known as the zona pellucida. To successfully implant into the uterine lining, the embryo must hatch out of the zona pellucida and attach to the walls of the uterus.
Assisted hatching is a lab technique that was developed when it was observed that embryos that had a thin zona pellucida had a higher rate of implantation during in vitro fertilization (IVF). Embryologists create a small hole in the outer lining using micromanipulation techniques under a microscope during the fourth day of embryo development.
Assisted hatching improves IVF success in women who are over 35 years or couples who have had multiple failed IVF cycles. It is thought that some women may fail multiple cycles of IVF because their eggs have a thicker shell, and assisted hatching can help with this problem.