I’m gonna start with the sperm freezing is a simple process. We require 1, 2 or 3 sperm samples in an IVF laboratory which are stored according to each IVF laboratory protocol. That’s why it’s how simple it is for a man, and I think it’s best to mention it so I can go into the actual question. There are actually two stages in the egg freezing process. The first stage is the stage where we prepare the lady to have the egg collection, and the second stage is the actual freezing procedure as you all know. Before you start an egg freezing process, you need to visit your IVF specialist or even your gynaecologist who knows about these things. The IVF specialist will assess your fertility by doing specific exams, like blood hormone measurements and the vaginal ultrasound, and whatever tests he or she might think are important to assess your fertility. Once that is done, the patient is prepared, we utilize a patient cycle, there are two ways that you can preserve your eggs. You can either preserve each egg that comes out of a lady during ovulation every month and freeze that egg every month. You can also undergo hormone therapy, so within one cycle, you can eject specific hormones to your body to grow more than one egg, hopefully, 5-10 eggs. If you choose a natural cycle egg freezing process that means that we follow the ovulation of a lady and just before ovulation we perform the procedure called egg collection. The lady is put under very mild sedation it’s no general anaesthesia, it’s mild sedation, and we aspirate the follicle, find the egg and then go to the second stage of freezing.
Most women opt for the second option they would like to store more eggs on one go. We place the patient under hormone treatment approx. 10- 12 days, we monitor the patient during this time to see how follicles are growing and once the follicle is ready, just before ovulation, we go through mild sedation but instead of operating one follicle, which is done on a natural cycle, we aspirate all the follicles. We find all the eggs, and then these eggs are taken into the IVF laboratory.
There comes the second stage of the egg freezing process, which is the freezing and storing phase. We collect the eggs, clean them and check which eggs are of good quality morphologically, and which eggs are mature. Only good quality mature eggs are usually cryopreserved. Nowadays, we use a technique called vitrification procedure. We have the highest percentage of around 85 to 95% success rate in freezing the eggs. As an embryologist, I always say to patients that an egg is the most difficult cell to freeze. The reason behind it is that the egg is the biggest cell of the body. That means that the egg has a larger quantity of water inside it. Unfortunately, as all of you know, when you freeze water, you create ice crystals if you do that in a cell that will rupture the cell. That is why we use vitrification, and that is why we have higher percentages of success rates during the freezing process.
Lastly, according to ESHRE guidelines, some patients have found their partner, but they are not ready to have a family yet. So you can also have embryo freezing process which is exactly like the egg freezing process, however, before freezing the egg, you fertilize it with a single sperm, or each egg is fertilized with a single sperm. You create an embryo which divides from 1 cell to 2 cells to 4 cells or to a blastocyst which is 150 cells, and you freeze it at that point. That is for patients that for whatever reason have found a partner and they want to delay having a family.