Some Background

I have already been through one egg freeze cycle, and I am going to be doing another one. Why? As it turns out one egg freeze cycle may not get enough eggs to give a good chance of having a baby. There are a lot of things that have to go right for the baby to happen. I am not a medical professional so this is probably an overly simplistic explanation, but in general this is what needs to happen: The eggs need to survive the thawing process.Then the eggs have to be successfully fertilized. Then they have to grow into an embryo that can be transferred into your uterus. The embryo has to implant successfully and continue growing into a baby. There can’t be a miscarriage. At every step along the way, some of the eggs don’t make it to the next step. So you can end up not having enough eggs to result in a live baby. Of course even if you have tons and tons of eggs, there are no guarantees. But overall, your chances increase the more eggs you have frozen.

One of the factors that affects how many of your eggs make it through the whole process is the freezing method. There are two main freezing techniques, slow freezing and vitrification. Vitrification is a newer technique and it seems to be more successful. For example, consider the following data from Pelin et al., “Age-specific probability of live birth with oocyte cryopreservation: an individual patient data meta-analysis”:

	Slow Freezing	Vitrification
Eggs surviving thawing process	65%	85%
Eggs fertilized successfully (of those that survived the thawing process)	74%	79%
Implantation rate (of fertilized eggs that grew into embryos and were transferred into the uterus, how likely were they to implant)	>8.9% under age 30, 4.3% after age 40	13.2% for age 30, 8.6% for age 40
Miscarriage rate ages 30-40	36%-41%	19%-22%
Pregnancy rate per 6 eggs thawed in 32-year-old eggs	9.2%	21.6%

So as you can see, pretty much everything goes better with vitrification: more eggs move on to the next step at every stage. In my previous egg freezing cycle, I froze 11 eggs using a slow freezing method.  As you may have guessed, I didn’t do this research until AFTER that first egg freezing cycle, or I would have sought out a clinic that had vitrification in the first place!

Let’s run the numbers  on my 11  slow frozen eggs: Let’s assume that there is one cycle in which 6 eggs are thawed (with a 9.2% pregnancy rate) and another cycle in which the remaining 5 are thawed (maybe a bit under 9% pregnancy rate).That is just not a high enough chance for me--I want to be much more sure about my chances of getting pregnant, so I am setting out on another egg freezing journey, this time with a fertility center that uses vitrification.

Currently I have an appointment scheduled for a consultation with the new fertility center. I am excited to get going with the new egg freezing cycle, and I am even hoping that I will get more than 11 eggs this time. (The clinic where I did my first cycle seemed very worried about over-stimulating me, so I wonder if they somehow ended up under-stimulating me instead.)