Research and Treatment Assisted Hatching Early embryos are covered by an outer coating called the zona pellucida . The zona holds the cells of an embryo together. After an embryo arrives in the uterus, the outer zona coating dissolves. Implantation cannot occur until the embryo hatches.
Natural hatching is less likely to occur for certain women.
Embryo implantation is one of the greatest barriers to success for IVF cycles. Benefits AH increases the success rate of IVF for certain women. The AH procedure may increase the rate of monozygotic twins. On the third day after egg retrieval, the laboratory staff will use a microscopic glass tube to place an extremely small amount of fluid on the outer coating of the embryo. This fluid dissolves part of the outer coating.