The assisted hatching procedure, like ICSI, is carried out by a technique known as micromanipulation. The embryos are placed in small dishes and stabilized by a holding pipette. On the opposite side, a laser is used to create a small opening in the zona (the egg shell). Assisted hatching was developed in response to the theory that some women may fail multiple cycles of standard IVF because their eggs have a thicker shell and because embryos with areas of thinning of the shell were observed to be more likely to implant. By creating a minor opening in the zona the result is a greater chance of the embryo “hatching,” or shedding its shell, allowing for a better chance of implantation in the endometrium. In addition, hatched embryos implant one day early, which may allow a greater opportunity for implantation to occur, particularly if the endometrium is advanced by the ovarian stimulation.