Early human embryos develop within an outer covering called a zona pellucida. Before the embryo can implant in the uterus, the embryo must break through this covering. In some cases, it appears that human embryos sometimes lack the ability to do this.
The technique of assisted hatching involves measuring the thickness of the zona pellucida in embryos that are candidates for the procedures. If an embryo has not initiated the thinning process naturally, a small “window” is created chemically in the wall of the protein coat, using a dilute acidic solution pulsed onto the embryo surface, through an extremely fine glass micromanipulation needle. The embryos are then implanted normally into the uterine cavity.
You may be a candidate for assisted hatching if you are 38 years of age or older, or if you have previously had one or more IVF cycles with failure of your embryos to implant, despite otherwise good results.