After transfer to the uterus, the embryo must implant in the uterine lining and continue its development. In order to do this it must break out of its “shell”. This shell is called the zona pellucida. Embryos may have a harder than normal shell or they may lack the energy needed to break out and complete the “hatching” process. Embryologists can assist this hatching by make a small hole in the zona pellucida of the embryo on the third or fifth day of the embryo’s growth. This is done through a specially fitted laser microscope. The cells of the embryo can then escape from this hole and implant at an earlier time of development when the uterine lining may be more favourable.
Some embryos grown in the laboratory may have a harder shell than normal or may lack the energy requirements needed to complete the hatching process. The embryologists can help these embryos achieve successful implantation through a technique called assisted hatching.
On the third or fifth day of laboratory growth and shortly prior to uterine transfer, a small hole is made in the zona pellucida of the embryo with a specially fitted laser microscope. Through this opening, the cells of the embryo can escape from the shell and implant.
Patients who are most likely to benefit from assisted hatching are:
- over 38 years of age
- mildly elevated Day 3 FSH
- multiple ART failures
- identified abnormalities with the zona pellucida.