Another microsurgical procedure performed in the ART laboratory is Assisted Hatching (AH). AH is a procedure performed on embryos prior to transfer to the uterus on Day 3 of embryo development. This is done in order to increase the chance of embryo implantation and pregnancy. Each human embryo is surrounded by a "shell" called the zona pellucida. The embryo must break out of this "shell" in order for implantation to occur. An unusually thick or hard "shell" is thought to reduce the likelihood of implantation and pregnancy. Therefore by creating an artificial opening in the "shell" the likelihood of implantation is thought to increase. Assisted hatching is most useful for the following types of patients.

	Patients older than 38 years of age
	Patients with elevated levels of follicle stimulating hormone (FSH)
	Patients with embryos thicker than normal zona pellucida
	Patients with previous multiple IVF attempts with failed imlantation