Assisted Hatching is a scientific technique used in in vitro fertilisation (IVF) that may improve the implantation of embryos into a woman’s uterine lining by creating an opening through which the embryonic cells can hatch out. Pregnancy cannot occur unless the embryo hatches. Just before embryo implantation, the developing embryo must “hatch” out of its outer shell (zona pellucida). Some embryos seem to have a thicker shell that may diminish their ability to hatch and reduce the likelihood that they will implant. This may be due to the age of the woman or other unknown reasons.