Assisted Hatching(AH)Assisted hatching is an embryo micromanipulation technique that was developed to aid in implantation of embryos. The rationale for this tehnique came from the observation that embryos that had a thin zona pellucida (outer shell) had better implantation rates during IVF cycles. Some women's eggs have thicker outer shells making it more difficult for the embryo to hatch.
Also, in some cases of mutiple failed IVF's it is thought that the embryos lack a sufficient amount of energy to complete the hatching process. If an embryo cannot successfully hatch it will not be able to implant itself in the uterus. There is a slight risk that the embryo may be damaged through this process; however, this maybe outweighed by the fact that hatched embryos implant one day earlier which possibly allows more opportunity for implantation to occur. There is a slightly increased chance of identical twinning in all its forms following assisted hatching.
An embryo (six to eight cells) is stabilized by a holding micropipette (an ultra fine glass needle). On its opposite side another micropipette containing an acidified solution creates a small defect in the zona pellucida. Care is taken to ensure that the defect is the appropriate size. The embryo is then rinsed to remove any excess solution and is retumed to the incubator. The transfer procedure is then carefully managed to prevent compression of the embryos.
Assisted hatching has aided many women in conceiving successful pregnancies through IVF after previous failures. It can dramatically improve the success rates for women who are considered to have a poor prognosis for IVF success (eg., older patients and those with elevated FSH levels).