Do fertility doctors recommend fresh or frozen donor eggs?
Patients undergoing egg donation may sometimes be offered oocytes preserved in an egg bank. Those who aren’t deeply familiar with the science behind the process may wonder if there’s a difference between fresh and frozen eggs. Do fresh eggs have a higher success rate over frozen ones? Or is it the other way around?
To help us understand the topic, we invited three experts to explain the differences between fresh and frozen eggs to us. They are:
- Dr. Maria Arqué, Fertty International, Spain
- Dr. Raul Olivares, Barcelona IVF, Spain
- Dr. Uljana Dorofeyeva, Intersono Clinic, Ukraine
Answer from Dr. Arqué
There is nothing inherent to the egg vitrification process that is going to make your eggs of better quality. The things that are important to consider are the egg donor herself, the age of the egg donor that in most countries, the legislation is that all egg donors must be between the ages of 18 and 35 years old maximum to make sure that the egg quality is not going to be an issue. The other things that have to be taken into consideration as well are how all the processes related to vitrification done in the lab. It’s very important to have a very high standard and very qualified and skilled biologists to perform all of the procedures. It is true that there are some studies saying that maybe in less than 5% of the egg donors that usually perform well with fresh eggs might perform a little more in a poor way when we use the frozen eggs, but in general, in more than 95% of the cases, the results should be the same. When we look at the pregnancy rates and the live birth rates, the results are comparable when we use fresh and frozen eggs. The advantages of using frozen eggs are that we usually have more than a wide variety of ethnicities of different kinds of egg donors, and there is no need to synchronize the cycle of the egg donor with the recipient, which means that usually the timeline for starting the treatment is much, much shorter. It makes it all much easier to organize for the patients and for the clinics. So, to conclude, I would like to sum up saying, vitrified eggs, with the techniques that we use nowadays are as good as fresh eggs.
Answer from Dr. Olivares
If I had to choose between fresh and frozen eggs, I will always choose fresh. It is true that the initial studies estimate that pregnancy rates are very similar, especially with regards to the use of fresh embryos. But there are also some big studies like the National EUS Registry that has confirmed that the pregnancy rate could be lower when we work with frozen eggs. On top of that, we need to be absolutely sure that when we work with frozen eggs, the number of embryos that we are going to get is lower. In our laboratory we need 9 frozen eggs to get 3 blastocysts. If we work with fresh eggs, we only need 6 of them, so we need 33% more eggs to end up with the same amount of good embryos. This could initially not be so important because the pregnancy rate we can accept that it is going to be fine, but the cumulative pregnancy rate which means the chances of getting pregnant in a single cycle can be lower. Remember that these cumulative pregnancy rates depend on how many embryos we get. So, the fewer the embryo seeds, the lower the chances that we can get pregnant. This is why whenever it’s possible, this is how it works in our egg donation program, we only work with fresh eggs.
Answer from Dr. Dorofeyeva
My name is Dr Uljana Dorofeyeva and I’m the medical director of Intersono Clinic. The question is: are fresh eggs better than frozen for IVF with donor eggs? In our practice, we use a lot of vitrified oocytes from our internal bank and the data for the initial year says that there is no statistical difference in terms of the results. We are very happy to use high quality, vitrified oocytes as their survival rate is very high—over 96%, as the blastulation rate and the clinical pregnancy rate are equal for fresh and frozen donor eggs. Fresh donor eggs are still used in our clinic and this used to be the gold standard. However, nowadays vitrified oocytes are considered more as a gold standard as there is no risk of not retrieving oocytes from a fresh donor. There is no need to synchronise the recipient and donor cycles and there is no risk that the eggs will not be retrieved. So, vitrified eggs from the bank are more predictable and are very successful in terms of treatment.