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Egg freezing vs. embryo banking: What’s right for me?

Sofia Rodrigues, BSc
Clinical Embryologist, Ferticentro
social-freezing-fertility-preservation
From this video you will find out:
  • What are the main differences between egg freezing vs embryo freezing?
  • What are the survival rates after thawing in egg and embryo freezing?
  • What are the main advantages and disadvantages of embryo freezing vs egg freezing?
  • When should you consider egg freezing?

Egg freezing vs. embryo banking: What’s right for me?

During this event, Sofia Rodrigues, BSc, Clinical Embryologist at Ferticentro, Portugal explained the main differences and advantages as well as disadvantages of embryo banking vs egg freezing.

Egg freezing and embryo freezing are two valid forms of fertility preservation. Both have the same steps involved at the beginning of the process, which involves stimulation of the ovaries so that the follicles can grow and egg retrieval. If a patient wants to cryopreserve her eggs, those are selected by the embryologist after the egg retrieval, and they will be immediately cryopreserved. If a patient wants to cryopreserve embryos, those eggs will be fertilized with chosen sperm, and they will be left in the laboratory in culture for 5 to 7 days until the embryo reaches the blastocyst stage, which is the ideal structure of an embryo to be cryopreserved. However, if a patient cryopreserves her eggs, she can come to the clinic when she wants to use those eggs, and then the eggs will be thawed fertilized, and the embryos will be created and then transferred.

The survival rate after thawing

There is always the chance of loss during the thawing process for both embryos and eggs. The egg survival rate is between 80 to 90%, while the embryo survival rate is higher than 95%. The survival rate of eggs is a bit lower than that of embryos because the eggs are single cells, and a single cell is much more fragile and much more sensitive to the process of freezing and thawing, it is more likely to be damaged in that process. The success of the thawing of eggs is also related to the egg quality itself, which is tightly linked with the age of the woman that wants to collect her eggs. It’s important to remember that the quality of the egg decreases with the increasing age of the woman. A younger woman has a higher chance of survival rate of the eggs.

On the other hand, when an embryo doesn’t survive the thawing, it is because the embryo is composed of a hundred cells and it gives them a stronger structure, which is more resistant to the cryopreservation and thawing processes. However, these survival rates alone should not be the main determinant to choose between cryopreserving eggs or embryos.

Egg freezing – advantages & disadvantages

One of the biggest advantages of egg freezing is that it doesn’t require sperm, so eggs are frozen and can be stored for a later date and used later in life. This is an optimal choice for single women who haven’t found a partner yet or haven’t decided if they want to use a sperm donor, and it also gives reproductive autonomy to the woman because she can preserve her own fertility independently whether she has a partner or not. This gives higher flexibility to make different choices. Freezing eggs brings fewer ethical considerations compared to freezing embryos because an embryo is a certain form of life, an embryo will implant and generate a living being, and it’s easier to discard oocytes rather than embryos if that’s the case.

The disadvantage of freezing eggs is a lower survival rate after thawing, it has a lower survival rate compared to embryos, and it’s hard to say how many eggs will survive the thawing. After they survive, it’s also hard to say how many will fertilize and develop into blastocysts. Therefore, more eggs are needed to improve the chances of pregnancy. It’s also important to remember that the egg doesn’t give a lot of information about its quality or genetics because it’s not possible to test it.

Embryo freezing

One of the advantages is that it has a higher survival rate after the thawing. It’s possible to monitor and see the development of a fertilized egg until the blastocyst stage, which gives a lot more information about the embryo. When the embryo reaches the blastocyst stage, it allows to do a biopsy, it’s possible to remove some cells of the blastocyst for them to be genetically tested. Thanks to this procedure, it’s possible to know if it is genetically normal and whether it can give a viable pregnancy or not. These advantages give a higher success rate when it comes to embryo freezing rather than egg freezing.

The disadvantages include the necessary use of sperm. Therefore, if a woman chooses a different partner later in life, she may not be able to use previously cryopreserved embryos because if both gamete providers split up, the woman cannot transfer those embryos without the consent of the other partner who created the embryo. This can raise some legal issues when it comes to transferring such embryos.

The choice between freezing eggs versus embryos depends on your current social situation and your goals. Although freezing embryos have higher success rates, freezing eggs gives more flexibility and more choices in the future. If you are a single woman and want to preserve your fertility, then egg freezing may be the best option for you, but if you and your partner plan to have children in the future but want to delay the pregnancy, then embryo preservation will be an option to consider. However, it is important to remember that couples don’t always stay together, and if you change your partner, you may not be able to use the embryos that you created before.

- Questions and Answers

Is the act of freezing painful, and are there any side effects on patients like losing natural fertility, bleeding, and early menopause?

The stimulation and the growing of follicles is a long procedure, it takes several weeks until we have full-grown follicles with eggs inside. We can consider it a bit painful because you will have injections every day. If you’re not afraid of needles, there’s no problem for you, during the egg retrieval itself, you are under sedation, so you don’t feel anything. The side effect could be overstimulation, you can feel some pain in your abdominal area. Nowadays, we have medication to attenuate those symptoms.

What has higher success rates, embryo freezing or egg freezing?

The preference depends on your social conditions, whether you are a single woman or you have a partner, but I would say that egg freezing for sure has a lot of advantages. I would advise doing embryo freezing as it gives a higher chance, but only if you are sure you want to have children with your partner. As I’ve mentioned, couples don’t last forever, and if something happens, you’re not allowed to use those embryos without the other partner’s consent.

If a woman passed her menopause, is it still possible to get pregnant with frozen eggs or embryos?

It is possible for a woman that has passed menopause to get pregnant but not with her own eggs, I’m afraid because if you’re in menopause, you don’t have available eggs of good enough quality to generate the embryos and then develop a pregnancy, you possibly might need to use donor’s eggs. Here in Portugal, you can still get pregnant until you’re 50 years old, so yes, it is possible, but with eggs from a donor, or if you have frozen eggs before or embryos, you can transfer the embryos even if you’re in menopause as long as your endometrium is receptive.  

I have only 4 frozen eggs preserved. Now at 47, I still have monthly ovulation. Is there the slightest chance that I can go through the process of preserving more eggs? How does the process work if someone has cysts on one egg stuck?

You can go through the process of preserving more eggs, although when a woman ages, the egg reserve also tends to diminish, so the probability of getting a lot of eggs is low. This is just something you need to confirm with your doctor because there are a lot of other factors that may influence the fact that you still have eggs or not. Regarding the cyst, this is more of a medical issue, so I cannot answer that question because I don’t have enough information on this, it’s best to check with a fertility specialist. It depends on a lot of hormonal factors, we need to do a lot of tests to know if it’s worth to do egg freezing, but yes, if all the factors are aligned and if you have a good egg reserve, why not, as long as you are properly evaluated.

Would the AMH number show how good the chance of egg preserving there is?

This can help with predicting the number of eggs that we will be able to get during the egg retrieval. The higher the number of eggs is, the better chance of getting a good number of eggs. It is one of the requested parameters to be analyzed before we do the egg retrieval and start the stimulation. This is something that is always checked before you can even start the egg-freezing process.
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Authors
Picture of Sofia Rodrigues, BSc

Sofia Rodrigues, BSc

Sofia Rodrigues, BSc is a Clinical Embryologist at Ferticentro, Coimbra, Portugal.
Event Moderator
Picture of Caroline Kulczycka

Caroline Kulczycka

Caroline Kulczycka is managing MyIVFAnswers.com and has been hosting IVFWEBINARS dedicated to patients struggling with infertility since 2020. She's highly motivated and believes that educating patients so that they can make informed decisions is essential in their IVF journey. In the past, she has been working as an International Patient Coordinator, where she was helping and directing patients on their right path. She also worked in the tourism industry, and dealt with international customers on a daily basis, including working abroad. In her free time, you’ll find her travelling, biking, learning new things, or spending time outdoors.
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