Slow freezing and vitrification both are the techniques used for the IVF process. However, only a handful of hospitals or centers use these techniques for IVF treatment in India but both are very beneficial for the woman who has issues with their ovulation but wants their babies.
During the IVF process female eggs are retrieved and kept with the male sperm in the Petri dish for fertilization and further successful pregnancy after the implantation of developed embryo but there are some women who suffer due to less number of egg production or due to production of low-quality eggs means they do not have the eggs which can be used for fertilization then such women go for freezing or donor eggs.
These are basically two methods of preserving the female eggs for further use as per the wish of the patient. If we talk about the vitrification then it is the flash freezing technique and is the modern method of preserving the eggs but if we talk about the slow freezing then as the name suggests it is the slower process of freezing eggs and it is also the traditional method of preserving eggs.
During the slow freezing method, the cell is cooled down very slowly at the decrease of 3-2 degree Celsius per minute and it is decreased until it reaches to the final storing temperature of the egg that is -196 degree Celsius or about -320 degree Fahrenheit. It is the ideal temperature for the preservation of egg so that without any loss of any of its quality factor it can be used for further pregnancies. This whole technique finishes in a couple of hours and in this process the all biological processes cease inside the cell preserved due to hours of processing time it is called slow freezing or controlled rate or slow programmable process of egg preservation.
As discussed above it is also known as a flash freezing process of egg preservation so it is the speedy method as compared to the slow freezing. In this technique egg cools down so quickly an reaches to the ideal point of freezing -196 degree Celsius and at this point the egg becomes glass-like or vitrified and even it is the process of few minutes that is why it is known as flash freezing.
Thus the basic difference between both the techniques is the speed as in the older technique processing time is of few hours but in the modern, it is of few minutes so this difference of processing time differentiates both the methods of egg preservation. Even some studies have claimed that modern method is better as they claim that time can destroy some properties of the egg so the speedy method of egg preservation is better however no clinical evidence has been given for the same. Thus the embryologists use both the methods for freezing the eggs.