IVF with donor eggs – are fresh eggs better than frozen?

If I had to choose between fresh and frozen eggs, I will always choose fresh. The initial studies indeed estimate that pregnancy rates are very similar, especially in regard 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 lowered when we work with frozen eggs. On top of that, we need to be 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 is going to be fine, but the cumulative pregnancy rate means the chances of getting pregnant in a single cycle can be lowered. 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.

Egg donation is currently changing quite rapidly in the UK. Historically, what’s happened is the donor and the recipient have had synchronized cycles so that the recipient never quite knows when the egg collection is going to be, how long the waiting list is because it depends on when a donor comes through that the match to, whether the donor gets enough eggs to share or donate because there tends to be minimum numbers and also the complexities of potentially having a donor and a recipient in the center at the same time – you don’t really want that just in case people start talking in a waiting room and over the last couple of years, a lot of clinics have moved to frozen egg donation so, instead of donating the eggs fresh, what you can do is freeze the eggs and you can build up a catalogue of egg donors and what can happen is if you donate your eggs in , for example 2020, our recipient may not use them until 2029. The logistics are that just that much easier you know exactly how many eggs you’re gonna get, recipients can pick when they’re going to come through for a cycle as long as the eggs are there it’s just much more logistically easier to do that. It’s just that some clinics will be better than others at that egg freezing program so, it’s not a case of how many egg freezes the clinic do but also how many egg thaw does the clinic do because until they’re thaw their eggs, they can’t really comment on the quality of their procedures in their egg bank program.

Another important question, frozen eggs versus fresh eggs. There are many egg banks nowadays that provide frozen eggs and we always get the question why not take frozen eggs and that advantage is very obvious, they are available right away, it is usually cheaper, you don’t need to synchronize them and so on and that is absolutely true, those are all advantages. Most fertility specialists have a  higher comfort level with more eggs for a couple of reasons. One- you have a fresh cycle, all of the eggs belong to you in the US. In Europe or other countries we know that you get batches but in the US a donor produces 20,25,30,35 or 50 eggs that all belong to you. This at the end of the day provides a much larger number of embryo’s. Something to remember in the process of IVF and egg donation, the number tends to go down a lot, for example, let’s say we have an egg donor from whom we have extracted 20 eggs. From those 20 eggs, probably about 15 or 16 are actually usable. Of the 16, we fertilise them and probably about 13 or 14 will become embryo’s. Of those embryo’s, we keep them in the lab to see which will keep developing to the final stage called day 5 or blast embryo’s, we lose around 50 percent of them so now we are down to around 7 embryo’s.
Of the seven embryo’s when we check them for chromosomes, there are only around 4 abnormal ones. So you can see how on an average of around 20 retrieved eggs you end up with around 4 or 5 usable embryo’s. We want to end up with at least 4 to 5 usable embryo’s because we take into account that there could be a miscarriage, a failed cycle and we also want you to have enough embryo’s for a sibling journey, so you can see when you use frozen eggs we only get batches of around 8 or 10. So from the beginning you work with half of the amount of eggs that you would work with if they were fresh. What we have learned with frozen eggs at least, in our practice, we successfully use frozen eggs, they thaw very well, so the survival rates of frozen eggs is very successful, I would say around 90 percent . They fertilise very well, so we get very good fertilisation and they produce a good amount of blast which is sometimes very similar to fresh. What we do know is that pregnancy rates seem to be a little lower than we have with fresh eggs. If you look at scientific literature, it is pretty much equivalent but our experience in the clinical practices is that pregnancy is a little bit lower, so it is a little bit lower pregnancy rate and you are working with fewer eggs and that is one of the biggest ones.
The third one, which is not a concern, but you will know that we have the answer, when we freeze embryos from fresh eggs, we retrieve the eggs and the eggs are fresh, we fertilise and grow them and we do a biopsy for genetic testing and we freeze them. Then when we need to use them, we thaw one embryo and transfer it back. When it comes to frozen eggs, we would retrieve the eggs, the eggs then are frozen, they have already been frozen once, then we thaw them, fertilise them and freeze them once more. We do not have any data that explains it as a concern but it is at the back of your mind, so I think that the advantage of frozen eggs is more financial, meaning women sometimes want to have frozen eggs and cannot afford to have a whole fresh cycle, the frozen eggs are absolutely a viable option. It is also a viable option if women, couples or singles or men want to have one child but again, there are the pros and cons.

This is not an easy answer. In most cases, the IVF fertility treatment with donated eggs is planned with synchronization of the donor and the recipient; which means, the fresh eggs are fertilized, cultivated, and transferred. But it’s not always possible. Sometimes, we have to use frozen donated eggs. Years ago, when the freezing, and storage, and thawing of eggs started the success rate was completely different. Nowadays, freezing and storage of eggs are on a high level, and we can say that it’s really comparable to the fertilization of the fresh eggs in the egg donation program. There is another difference between using fresh eggs in the donation program and frozen eggs, if it’s fresh eggs, then we need psycho-synchronization. If it’s a donated frozen egg, we can use it, and we can prepare only the recipient. So, it’s not according to the plan and schedule of the synchronization program in egg donation, it could also be more according to the patient – to the egg donation recipient.

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 we have to consider are how all the processes related to vitrification are done in the lab. It’s very important to have a very high standard and very qualified and skilled biologists to perform all the procedures. There are indeed some studies saying that maybe 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. 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 the clinics. So, to conclude, I would like to sum up by saying, vitrified eggs with the techniques that we use nowadays, are as good as fresh eggs.

My name is Dr Uljana Dorofeyeva. The question is: are fresh eggs better than frozen for IVF with donor eggs? In our practise, 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 synchronize 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.