Prior to embryo attachment on the uterus, the embryo is hatched from the outer layer protecting the embryo called zona pellucida. This process is necessary for the embryo implantation to occur and establish a pregnancy.
Scientists introduced a method to aid the process of hatching by making a small hole on the outer layer. This can be done by a microtool/micropippete or by the use of a microlaser. Another method for assisted hatching is the use of a weak acid to thin the zp, although this method is rarely used in the clinical setting.
Assisted hatching (AH) has shown to improve embryo implantation and pregnancy rates in different patient groups. The procedure has shown to benefit patients of advanced age, patients with abnormally thickened ZP and patient with previous IVF failures. Also recent findings suggest that this procedure increases chances of success of frozen embryo transfer cycles possibly due to the hardening of ZP imposed by the freezing-thawing procedure.