After the fertilized egg develops into a blastocyst, it breaks the zona pellucida (enters, hatches) and becomes able to implant in the uterine lining.
Hatching usually takes 5 to 6 days, but in cases where this is not possible, assisted hatching (AHA) is performed to make a hole in the clear zone.
There are several methods, but the most popular is the laser method.
A case where the
clear zone is hardened
This is the skill used to open a hole in the zona pellucida of the blastocyst and or embryo that is to be transplanted.
To break the zona pellucida and the cell coming out is called “hatching”, and when the cell that comes out is attached to the endometrium pregnancy is achieved.
Regularly after fertilization they will naturally hatch around the fifth to sixth day, but there are situations when the zona pellucida has hardened, or the blastocyst’s power itself will not hatch.
What works for these cases is AHA.
There is the method of dissolving the zona pellucida with the medicine called acidic tyrode, the method of opening hole by poking it with a needle and causing friction with a glass tool, and there are handful of others, but recently by use of laser has become the mainstream method.
Laser AHA〔Zona opening〕
Laser AHA〔Zona thinning〕