In some cases, it is necessary to make a small hole in the shell (zona pellucida) of the embryo with a laser or chemical to aid in the IVF process. This procedure, known as assisted hatching, is most commonly recommended for women who have had failed IVF cycles, poor embryo development, are age 38 or older or have thickened embryo shells. It is also common for those patients who undergo ICSI as part of the IVF procedure. Assisted hatching is most often performed on embryos that are transferred on day three and studies show that this process improves both pregnancy and implantation rates in these couples.