Assisted hatching is an additional procedure that can be performed in patients who are undergoing in vitro fertilization (IVF) treatment. The embryo is surrounded by a hard outer layer of cells called the zona pellucida. This outer layer of cells can be thought of as the “shell” of the embryo. The embryo must “break-free” of this “shell” in order to implant in the uterus and develop into a pregnancy. Assisted hatching is a procedure where we can assist the embryo to “hatch” from its’ “shell” by creating a small perforation in the zona pellucida. It is believed that a perforated zona pellucida increases the chance the embryo will hatch and successfully implant.
In a natural pregnancy when the embryo reaches the blastocyst stage of development the zona begins to thin. The thinning process is facilitated by the repeated contraction and expansion of the blastocyst which alters the elasticity of the zona. Once the zona is sufficiently thinned it tears allowing the embryo to hatch. Embryos that do not hatch will not be able to implant.