Assisted Hatching is a procedure, which involves creating a small opening in the outer coating of the embryo, the zona pellucida.
Assisted Hatching is done when the embryo has reached at least the six to eight cell stages. This opening allows the cell mass to more easily hatch out following embryo transfer, a factor that in theory facilitates embryo implantation by insuring contact with the lining of the uterus. Initially, Assisted Hatching was used in selected situations such as women over the age of forty, those with unusually thick zona pellucidae and where previous IVF attempts had resulted in failure.
Assisted hatching is now performed in our IVF laboratory routinely in all cases of embryo transfer. While it was debated that not all fertility clinics performing Assisted Hatching have had similar results, it should be understood that there are currently several ways of creating the opening ranging from use of an acidic solution to application of a special type of laser. It is also important that the size of the opening, the way in which the embryos are transferred following hatching and quality of the embryos at the time of hatching are critical in achieving success. It must be emphasized however that Assisted Hatching does not change the genetic composition of an individual embryo. Even though the overall implantation rate can be helped by Assisted Hatching, the loss of a particular pregnancy is an age dependent event that is determined primarily by the chromosomal makeup of the pregnancy.