What is Assisted Hatching and when should it be performed?
Assisted hatching is a laboratory micromanipulation technique carried out by experienced embryologists that entails making a very small perforation in the zona pellucida of the embryo. In some cases it is thought to enhance embryo implantation.
At present assisted hatching is performed in two different ways:
The chemical method: The embryo is held by a holding pipette and tyrode acid is placed in a small area on the embryo with a micro-pipette until a small hole is made in zona pellucida
Physical Method: This method consists is using an infrared diode laser to open a small hole. The hole is created due to the denaturalization of the proteins of the small area of the zona pellucida where the laser energy is released.
This method is very fast and easy to perform.
At ProcreaTec we use assisted hatching in two different cases:
After devitrification of Day+3 embryos before embryos transfer
When Preimplantation Genetic Diagnosis is going to be performed on Day+3. This facilitates the biopsy.
At ProcreaTec, we have found that there is a higher implantation rate is we use assisted hatching with vitrified Day+3 embryos. The zona pellucida at times can act like an outer shell and make things difficult for the embryo to “hatch” and implant. The small perforation that is made helps the cells that make up the embryo find their way to the endometrium once the embryo is transferred to the uterus.
This method can only be performed on Day+3. This is because on Day+4 compaction of the embryo occurs and on Day+5 the embryo has 2 different types of cells and there is no reason now for implantation to be difficult. On Day+5 the trophectoderm cells (which will later become the placenta) are firmly stuck to the zona pellucid and the probability in hurting the cells increase considerably so assisted hatching is not performed to enhace implantation on that day.
At ProcreaTec we have a laser which attaches to the microscope so the embryologist can see the embryo perfectly and where she is working (see header photograph).
It is important to use the best technology available to increase the possibilities of achieving pregnancy at every stage of treatment.
A blastocyst hatching naturally