In order for the advanced embryo to implant in the uterine wall and to continue development, it must break free of its shell, which is called the zona pellucida.
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 at a somewhat earlier time of development, when the uterine lining may be more favorable.
Women who are most likely to benefit from assisted hatching are those:
- Over 38 years of age
- With mild elevations in their day 3 FSH levels
- Having repeated failures of ART cycles
- With embryos that have abnormal appearing zonae, as determined
- Through close inspection by the embryologists
If performed improperly, creating this window in the zona pellucida can harm rather than help the chance for establishment of a pregnancy. Our embryologists have performed this technique for many years and have found it to improve pregnancy and delivery rates in the poor prognosis patient.