This stage of treatment evolves in laboratories by experienced embryologists. In the cases where, after the sperm preparation, its parameters (concentration, mobility, and morphology) are at normal levels, the embryologist, a few hours after the egg retrieval, places a certain number of activated spermatozoa in each petri dish containing the eggs in a specific growing agent.
The following morning the eggs are examined under the microscope to verify whether they have been fertilized or not. The embryologist notes the number of eggs that have been naturally fertilized and monitors their smooth progression for the next 2 or 3 days where the fertilized ova remain in the laboratory and continue to grow.
In standard IVF treatments, there is no other intervention. The sperm come to contact with the egg on its own and one of them penetrates and fertilizes it.
Intracytoplasmic Sperm Injection (ICSI)
If the sperm sample is of low quality or if there is a history of previous IVF fertilization failure then intra-cytoplasmic sperm injection (ICSI) is used. It is actually a microscopic surgery performed on the egg.
ICSI happens at two times after the egg retrieval.
To begin with, the ova need to undergo a specific treatment with an enzyme (hyaluronidase) to remove the granule cells surrounding the translucent zone.
The second phase is the main phase of the injections. The treated eggs are placed in petri dishes, in a small drop of cultivating agent each. In the specially equipped microscope, with the help of a microcontroller, they are immobilized by means of a thin glass pipette. Another thinner glass pipette (similar in size to an injection needle) serves to collect and inject a sperm into each egg. Each injection lasts for a few seconds.
Intracytoplasmic Sperm Injection is a safe method, as has been proven by the thousands of children born around the world.
ICSI Microencapsulation is appropriate in cases of:
- Men with a serious problem in the count or the mobility of their sperm or even a complete lack of sperm in their semen (azoospermia).
- Inexplicably low rates of fertilization or fertilization failure in previous attempts with conventional IVF treatments.
In older women with a small count of eggs that usually have a hard cortex.