During this session, Dr Kristýna Frühaufová, PhD, Head Physician of GYNEM Fertility Clinic, Czech Republic discussed fertility preservation and egg freezing, the process, benefits, and considerations of egg freezing.
In general, social freezing refers to the elective retrieval and cryopreservation of both oocytes and sperm when there is no medical indication. Preservation of oocytes gives women the chance to have their own genetic children later in life. We also see a trend of postponing childbirth to the third and fourth decades, which goes hand in hand with this trend in the population.
The map presented on the slide shows where social freezing is spread worldwide. In many places in Europe, social freezing is common, as well as in the United States and generally North America. It’s quite popular in Brazil, for example. However, some blank spots indicate social freezing is not carried out in those countries, such as Australia.
Social freezing has been quite a new method. It has become widespread with the introduction of vitrification, which is the fast freezing of oocytes. This method enables better survival of oocytes after the thawing process. Vitrification of oocytes was introduced in 2011 and has been used since then. Since 2011, social freezing has increased all over the world.
Female fertility is age-dependent, meaning the younger the woman, the higher the chance of conception. We know that fertility and ovarian reserve decrease with age. The age of 35 is usually considered the border when we know that the rate of aneuploidies, which means abnormal embryos, tends to go high.
To evaluate female fertility, several tests are required, such as the hormonal profile, especially AMH (Anti-Müllerian Hormone), which gives us an idea about the functional capacity of the ovaries, and the antral follicle count. Combined with AMH, these tests give us an idea of how the ovaries will respond to stimulation. AMH peaks usually around 20 years of age, so 25 to 30 is the best time to conceive a child because women by then have the highest AMH and the highest quality of oocytes. After the age of 35, AMH drops and starts dropping very steeply after the age of 40.
Social freezing generally requires stimulation of the ovaries to ensure more oocytes mature within one cycle. We can evaluate the response to stimulation based on age, AMH, and body weight. These are the main factors that define and guide the type of stimulation, dosage of medication, and the optimal number of oocytes retrieved. The retrieval of oocytes is done under anaesthesia and takes about 10 to 15 minutes.
There are some rare complications linked to this procedure. The most common ones are side effects of the stimulation, such as mild headaches at the beginning and some weight gain. Late complications might include ovarian hyperstimulation syndrome and rare complications during anaesthesia, which are usually mild and don’t require prolonged observation. These are most commonly seen in overweight and obese patients. Complications linked to the retrieval itself, such as bleeding from the vagina, can be dealt with during the procedure. Very rarely, intra-abdominal bleeding might require referral to a hospital for observation or laparoscopy, but this is very rare (about 1 in 1000 patients).
The optimal age for social freezing is under 30 years. Women between 35 and 38 might benefit from social freezing, depending on their AMH level. Higher AMH indicates that more oocytes will be gained during stimulation, increasing the chances of a successful pregnancy. After 40 years of age, it is still questionable.
The objective of frozen and thawed oocyte cycles is to have comparable success rates to using fresh oocytes. About 95% to 97% of oocytes will survive the thawing process and fertilization rates are around 70% to 80%, depending on the quality of the semen. The success of the procedure is mainly defined by the woman’s age at the time of oocyte freezing. Patients often ask about the optimal number of oocytes to be stored. The target number should be between 15 and 20 oocytes for women younger than 38. However, for women between 38 and 40 years, we need 25 to 30 oocytes. For women over 40 years, we need 30 plus oocytes. Ovarian capacity drops with age, so multiple stimulations may be required to obtain a sufficient number of oocytes.
Looking at the recent data, when the frozen oocytes have been used and fertilized, we know that there is no high risk of any congenital abnormalities, and this overall risk is comparable to women who have conceived naturally or with the standard IVF process. The risk of fetal loss due to aneuploidy may be reduced by using younger oocytes, which means, for example, when you freeze your oocytes at the age of 25 to 30 and then use them after the age of 35, you still have the same low risk of aneuploidies linked to the age when the oocytes were frozen.
When you look at the primatological outcomes, which means how the children are born, there is no difference between children conceived using frozen oocytes or those conceived normally and spontaneously. There is no obstetric or perinatal risk linked to oocyte freezing.
One of the interesting topics is the actual usage rate of frozen oocytes. We know that only about 15% to 20% of women come back to use their oocytes. There are multiple reasons for this, depending on the country and specific legislation. For example, if a woman is still single in some countries, she cannot use sperm from a donor to fertilize her own eggs. Some women, get pregnant naturally over time.
At the moment, in the Czech Republic, it’s possible to store oocytes for 8 years, but most likely the storage period will be unlimited because the medium used for freezing doesn’t wear out over the years. This is simply the current legal data, which keeps on changing every year as new data is published on this topic.
There are also some ethical points to social freezing. On one hand, social freezing gives women more reproductive autonomy and enables them to decide when they want to get pregnant. Even at an advanced age, they can use their own genetic material. On the other hand, one downside of social freezing is that it might promote late maternity. It might give some false ideas about delaying the time of pregnancy, and the commercialization of this topic in medicine should be avoided.
It’s also possible to preserve embryos, which have been widely used for decades in IVF. However, you should bear in mind that the embryo belongs to the couple. This means that if you create and freeze an embryo with a partner and then break it up, you would need their approval for the cryo transfer. There are also ethical questions linked to preserving embryos. It depends on how you perceive the embryo—whether as a living being or as a tissue. Some people are not willing to discard embryos, and they might be donated in some countries. There are lots of ethical questions linked to that.
We know that the optimal age to become pregnant is up to 35 years. Advanced maternal age is linked to elevated risks of pregnancy-related complications such as diabetes, hypertension, preeclampsia, preterm delivery, and even higher rates of miscarriage in the first trimester.
Oocyte preservation offers women the chance to have their own genetic children later in life, which might reduce anxiety, especially in some difficult social situations. However, the optimal age to store your eggs is before 35 years, with a target number of 15 to 20. Patients should be counselled regarding the risks of delayed motherhood and family planning in general.
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Perhaps. We do have lots of requests from women after 40 years of age, and we always try to evaluate and see what are the realistic expectations. As I said, we know that we need 25-30+ eggs, which is something that, when you’re over 40, cannot be achieved with 2 or 3 stimulations. For that, you would most likely need 5 or 6, which is quite a lot for the body.
The reason why you need so many eggs is that most of the eggs will carry some chromosomal issues already. This guarantees, let’s say, a 60-70% chance of having a live birth. Even with 30 eggs, you don’t have a 100% likelihood of having a healthy child. So, it’s quite a lot to take, both financially and for the body.
If I can imagine a PCOS-like woman with a high AMH, and we could achieve this target number of eggs within, let’s say, 3 stimulation cycles, then we would most likely go ahead with that.
This wouldn’t be possible in the Czech Republic because we don’t treat single women. Emma must come from a different country with different legislation. You always have to look at the whole case within the framework of the local legislation.
At the moment, the survival rate of eggs and embryos is the same. Speaking of our lab, we freeze eggs quite often, and with the use and widespread of vitrification, it’s equal. If you were my client, I would only have the chance to freeze the eggs. There wouldn’t be the option of fertilizing the egg with donor sperm. That’s the law here in the Czech Republic.
So, just to clarify, freezing eggs is possible if you are single. However, if you are single and would like to try with a sperm donor to have embryos, it’s impossible to do so here. Different countries have different laws, so we always need to check that first.
It’s the same stimulation as for IVF. We try to pick the best medication and the best protocol suited to the patient. It’s tailor-made for each patient, so there is no general answer to that.
Mainly, it involves gonadotropins, meaning injections for about 10 to 14 days, followed by the oocyte retrieval.
Yes, it’s individual and has to be judged by the ultrasound, the AMH, and the hormonal profile. But overall, as I said, we need 30 eggs at least.
This means a lot of stimulations need to happen to get that number, which is one of the reasons why IVF over 40 becomes difficult. The ovarian capacity drops, and you need more eggs to have one good-quality embryo.
We use sedation or general anaesthesia because the retrieval itself is painful, especially when you have multiple follicles. The pain is spread through the peritoneum, which is a membrane that covers the whole abdomen. This is something that cannot be anaesthetized locally. Therefore, there’s usually no option to use local anaesthesia for the retrieval.
If you have a fibroid, in most cases, you can move the ovaries around. The ovaries usually don’t stay in place unless you have adhesions binding the ovary to the uterus. Once you have stimulated the ovaries, they tend to drop inside the pelvis, making them reachable.
We can also do a transabdominal puncture if the ovaries are high up and not accessible through the standard vaginal route. Another option is to puncture through the fibroid, which is also technically possible. Sedation would still be necessary due to the pain involved in these procedures.
Yes, puncture through fibroids is very painful. The retrieval itself is painful, especially when you have multiple follicles. The pain is spread through the peritoneum, which is a membrane that covers the whole abdomen and cannot be anaesthetized locally. Therefore, there’s usually no option to use local anaesthesia for the retrieval. I had a patient who was afraid of undergoing anaesthesia and had 50 follicles. She made it without anaesthesia, but it was the most uncomfortable procedure for both of us.
The fast-freezing vitrification process shouldn’t affect the DNA. The egg is the biggest cell in our body and has a lot of water. Slow-freezing methods used before vitrification didn’t work well for freezing eggs. With the introduction of fast freezing, the quality of the eggs, as seen in pregnancy and clinical outcomes, should be the same. The quality of the DNA remains unaffected, and we don’t see higher rates of abnormalities with this method. It is a safe procedure.
Social freezing is a good tool, but there is an age limit. Freezing before the age of 35 is ideal. Between 30 and 35 is the best age range, as doing it too early might mean you won’t use your eggs because you might find a partner and get pregnant naturally. It’s usually between 30 and 35 when people start considering their future fertility. This is when you might decide to have the right partner to start a family or start getting anxious about future fertility.
