An embryo is created from the union of a sperm and egg in the in vitro fertilization process. After incubation, the embryo is transferred back into the uterus using a small catheter. Once inside the uterus it must “break free” of its surrounding shell (zona pellucida) and attach to the endometrial lining.
Assisted hatching involves etching a small hole in the zona pellucida prior to transferring the embryo to the uterus. It is thought that the opening makes it easier for the embryo to hatch and implant. It is made with a small needle using micromanipulation tools, chemically using acidified Tyrode’s solution, or mechanically using the laser.
Assisted hatching is most often used in patients who repeatedly fail to conceive in ART cycles, when there are poor quality embryos and women over the age of 38.