Assisted hatching or ‘zona drilling’ consist in perfoming a small hole in the zona pellucida of the embryo (a layer covering the embryo). As women get older, the zona pellucida may become hardened and tougher making it difficult for the embryos to hatch. With assisted hatching, once the embryo reaches the blastocyst stage, it can break out of it’s zona pellucidae much easier thus facilitaing better implantation rates.
How is the assisted hatching performed?
For the assisted hatching is necessary to hold the embryo with a holding pipette (a thin glass tube) and an small hole in the zona pellucidae is performed using acidified solution (acid tyrodes solution).