Are frozen eggs better than fresh? Is there any difference at all?
Anybody who consider IVF treatment faces a lot of difficult decisions. Suddenly you need to find yourself in the vast new world of medicine. It’s not difficult to start to feel overwhelmed. It may seem as if you were discovering a whole new planet in the galaxy. And then at once, you need to know if frozen oocytes are better than fresh? A new question arises after the previous question. Is there any difference at all? How it affects your IVF cycle if it has any influence at all? And if so, does it mean that the success of your treatment depends on this decision? What are the advantages to choose frozen egg donation over fresh? Does it play any role in the process and enforces some other steps? Is it possible that by making this choice it will be easier for you as a patient or it has nothing to do with it at all? Is it related to the success rates? And so on, on and on…
To help you stop struggling and to provide you with all the facts from the reliable source we did the webinar covering the topic: Fresh or frozen oocytes for your IVF with donor eggs? Is fresh bread better than the frozen one?
This time our expert is Dr Hana Visnova from IVF CUBE [Czech Republic].
All those complicated terms and medical matters are difficult to understand and what to say about execution. It may happen that diagnosis is uncertain, that recommendations are demanding and everybody repeats that the time, relaxation and patience are most desirable. And you don’t feel you have any time and patience. At all. Our webinars help you find the answers for all IVF questions you may have and you can ask these questions live during the live event.
Dr Visnova begins her presentation by speaking about the difficulties fertility specialists experienced with egg freezing.
As some of you may know, the human egg is one of the largest cells in the body – with a diameter of about 0.1 millimetre, it’s usually visible to the naked eye. Because of its size and of the water quantity inside the cell, preventing ice formation became a major issue. During the early days of fertility treatments, it was believed that because of the slow freeze method which was used at the time, only one in a hundred frozen eggs would result in a pregnancy.
In 2007, however, a new method was developed – vitrification, which drastically improved the survival rate of oocytes, as well as the pregnancy rate – five pregnancies can now be achieved from a hundred frozen cells, rather than just one. Sperm freezing, comparatively, is uncomplicated; the method has been known for about sixty years and from the earliest attempts has enjoyed high success rates. Because of the characteristic of human
sperm, it is much easier to cryopreserve when compared to egg cells. From the infertility clinics’ perspective, egg banking offers a major advantage – it makes the entire treatment process much simpler to plan, as the need to synchronize cycles between the donor and the recipient simply isn’t a factor. Additionally, the process allows more time for additional testing, if needed. In some countries, such as the United States, clinics are allowed to use donated eggs from affiliated fertility institutions, which significantly expands the available donor pool.
If we look at egg banking from the patient’s perspective, advantages can also be found; for instance, about 5% of fresh egg donation cycles are cancelled due to donor-side issues, such as hyperstimulation. Obviously, banked eggs bypass that issue entirely.
Additionally, it is much easier to find a donor of a matching phenotype when opting for a banked egg transfer – which cuts down on the waiting time. Another advantage is the complete lack of a down- regulation cycle, avoiding the possible side effects from the medications used in such cycles, making the treatment much more comfortable.
Because of the relaxed time constraints, treatments could be scheduled to align with the natural cycle – again, reducing the need for additional medication. This helps patients and clinics schedule treatment to respect job commitments and travel arrangements.
The big question, however, remains – does egg banking provide identical or comparable success rates to treatments using fresh egg donations? Dr Visnova’s clinic, IVF Cube, commissioned a study to help determine an answer. They were also interested in whether frozen oocytes resulted in similar numbers of good quality embryos when compared to fresh donor eggs, and whether the implantation and successful live birth rates are comparable.
Their analysis compared 266 fresh egg donation cycles to 63 cycles using frozen donor oocytes. The total pregnancy rate for fresh eggs was 68.05%, while that of the frozen oocytes was 42.86%. Of all the egg cells suitable for ICSI fertilisation per cycle, 100% of fresh eggs and 93% of frozen oocytes were suitable.
The fertilisation rates per cycle were 84.81% and 72.97% for fresh and frozen oocytes, respectively. Fresh eggs resulted in at least one high quality embryo in 96.24% of all cycles, with frozen ones trailing behind at 61.9%.
Dr Visnova sums the study up as such: the numbers indicate that higher numbers of frozen oocytes are required to ensure the generation of a good embryo at the blastocyst stage. Conversely, on average, almost two surplus high quality embryos are produced each cycle, which can be frozen for future use.
When it comes to results, we can see a marked statistical difference between using frozen and fresh donor eggs. On average, IVF Cube required only around 7 fresh eggs to achieve a successful pregnancy, while it needed twice that amount in frozen oocytes for the same result. Because the clinic used about 11 eggs per cycle during the study, some patients did not achieve a successful pregnancy during the first cycle.
Dr Visnova’s conclusions are then as such: while fresh donor cycles are time-consuming and require more management from both the patient and the clinic to arrange a workable schedule, fresh oocytes have a higher cumulative success rate and have a higher chance of producing surplus embryos which can then be used in future treatments. In her opinion, the freezing and banking of donor eggs is a waste of biological material; her clinic continues to recommend fresh donation cycles for patients.
Questions and Answers from the event
Can leftover embryos be shipped to my home country, or do they need to stay in the clinic’s bank?
It is usually possible, but depending on which country you originate from, there might be some legislative restrictions placed on embryo transfer. Usually, that’s not a problem, but double-check to be sure.
How can one find egg donors of Afro-Caribbean descent?
Your best bet would be to contact clinics either in the Caribbean or Africa. This particular phenotype is not very common in Europe. (There is however a significant Afro-Caribbean population living in Great Britain – perhaps their clinics have donors of such descent?)
I have adenomyosis and my thyroid level 7.2. I had a stillborn child and a miscarriage. What are my options?
It’s hard to recommend a course of action without knowing your full medical history. You can contact us at firstname.lastname@example.org to have your message forwarded to IVF Cube.
How many of the women who got pregnant gave birth to a healthy child? Is there a difference between frozen or fresh blastocysts or eggs?
The pregnancy rate for frozen eggs was 42.86%, while it was 68.05% for fresh eggs. There is a marked difference between frozen eggs. The study we described during the presentation did not compare the success rates of frozen and fresh blastocysts – we were only concerned with eggs, not embryos.
I have a slightly different question – does my diet have an impact on implementation? Can gluten or lactose intolerance cause implantation failure?
Not exactly – underlying immunological issues can cause the implantation to fail. Gluten or lactose themselves may have many causes; for instance, gluten intolerance is a symptom of celiac disease or dermatitis herpetiformis, both of which are immunological issues. If you experience these sorts of issues, it’s crucial to determine what caused them to appear in the first place.
What year did vitrification replace slow freezing as the preferred method for preserving oocytes and embryos?
Vitrification was introduced in 2007, although due to legislative issues it was not introduced in many countries straight away. For example, it was still marked as an experimental procedure in the United States until 2013.
If I understand correctly, your advice is to choose egg donation?
Yes, I do. I know the advantages of frozen egg donation, but I also understand the downsides. In my professional opinion, a fresh donation is still the best option to achieve pregnancy.
Which criteria are used to select donors? Do you find donors that look similar to the patient?
We provide patients with a donor matching form, in which they describe their phenotype and other characteristics. They also provide us with pictures of themselves – all of this data is then used to find the best match for the patient.
Does the donor selection process change depending on whether the donation concerns frozen or fresh eggs?
No. The real differences are with the technical process during the donation – for fresh eggs we monitor both the donor and the recipient, because they need to go through the stimulation process in order to synchronize their cycles – because of this we are able to present patients with more information on the donor, as we are monitoring the donor’s health throughout the stimulation process. That information usually isn’t available with egg banking.
Does the term “pregnancy rate” mean successful pregnancies – that is, resulting in a live birth? Or does the pregnancy rate only consider clinical pregnancies no matter the outcome?
The term “pregnancy rate” in our study referred to pregnancies which ended in successful live births. If a child born from an egg donation is diagnosed with a genetic illness, can the clinic provide additional information if it is necessary for the further treatment of the child?
Of course. Although these situations happen rarely, in such cases the donor will be contacted by the clinic to ask them to return for additional testing and to provide more medical history that will be then made available to the child’s family.
Are there any risks associated with freezing embryos for PGS?
The implantation rates for embryos frozen for PGS are around 60% to 70% worldwide, while their survival rates are about 95%. That means that in around 5% of all cases, the embryo does not survive the thawing process following vitrification.
So if I understand your study correctly, a blastocyst from a fresh egg has about more than a 60% chance of resulting in a live birth, while it’s only around 45% for frozen eggs?
Exactly. Similar work has been recently published in the United States and their findings are aligned with ours.
Do you offer Skype consultations? How much do they cost?
We do offer Skype consultations and they are free of charge.
How long can embryos be stored at IVF Cube? Is there any limit?
It’s not a question of our clinic’s policy, but of our country’s legislation. The Czech Republic legally allows us to store embryos for no longer than 10 years. Medically speaking, the limit is likely longer, but in this case we’re limited by the law.
If a patient is 49 years old and has a myoma, is it more difficult to get pregnant than for a younger person?
That depends on the size and location of the myoma. For instance, myomas located under the uterine
lining do affect implantation rates. Then there’s the issue of age. While an implantation can be achieved relatively easy using donor eggs for patients in that age group, other issues related to age can arise during the pregnancy itself, such a preecclampsia, abnormal behaviour of the liver and kidneys.
What was the Study from the United States that you just mentioned?
Do you recommend endometrium receptivity mapping for fresh and/or frozen eggs?
The procedure you mention has nothing to do with the eggs themselves – endometrium mapping is one of the procedures used to fight repeated implantation failures. If you have experienced several failed implantations, it’s one of the methods used to determine the cause of failure.
I’m 39 years old. Do I have a chance to get pregnant with fresh eggs from a donor? Does my age influence the pregnancy rate with egg donation?
In your age group, the pregnancy rate depends on the amount of embryos you choose to implant. If you implant a single embryo, due to your age your chance of getting pregnant would be around 50%. You can increase that up to 75% by choosing to implant more embryos, however you need to be mindful of the possibility of achieving a twin pregnancy. At your age, fertility specialists tend to avoid twins, as they can result in complications further down the line.
If there are more than one good donor matches, how does the clinic determine which one to use? Is it a team decision?
While the donor preparation is usually a team effort, the final say in the donor matching process belongs to two members of the team: the medical director and the embryologist(?) as we need to maintain the mandatory anonymity.
Who are your donors?
Our donors are young, the average age group is 29, with about two-thirds of them already being mothers themselves. The rest are usually students who haven’t yet given birth. Most of them come from the Czech Republic or Slovakia.
Do you usually perform a single or a double embryo implantation?
It depends on the patient’s medical history and age, as well as recommendations by their fertility doctor. The final decision, however, belongs to the patient, as some couples do not want to risk a twin pregnancy. Conversely, patients with repeated embryo implantation failures often opt for a double transfer as they are afraid of another failed.
What is the average age of patients seeking egg donation in your clinic?
In 2018, the average age of egg donation patients was around 42 years old.
Does your clinic make decisions about donor recipients based on the recipient’s age, or health?
Both, technically. The recipients are asked to provide us with their entire medical and family history so that we can avoid any potential complications and issues that may arise over the course of the treatment. Regarding the age, we have a maximum legal age limit of 49 years old. The Czech Republic does not allow older women to receive egg donations.
If a patient does not have her period, do you induce it with hormones and wait for the uterus lining to thicken before implanting the embryo?
Exactly. We use estradiol to induce the period and we monitor the patient’s uterine lining. Once an ultrasound confirms that the lining is thick enough, we start the patient on a five-day course of progesterone, which then gives us optimal conditions for embryo transfer.
If both the egg and sperm donors are healthy, would you recommend PGS testing?
No. Donors are already pre-tested and screened for genetic diseases, which makes additional testing redundant. It’s still available for patients who want to be sure, although it’s highly unlikely that embryos from healthy donors could be genetically abnormal.
Can my partner give sperm if he’s over 50 years old?
There is no age limit for male partners – he could be even older than that.
I thought PGS helped to reduce potential miscarriages, for example those resulting from aneuploidy.
It does, however it’s redundant in egg donation cycles, as egg donors are too young to have a significant chance of producing low quality eggs which could result in an aneuploid embryo. Testing is, of course, available nonetheless to patients, and while – again, only in egg donation cycles – is only really recommended if there is a history of aneuploidy in the family, it can still be performed if the couple
wishes to do so. However, the additional cost and time investment need to be considered as well.
For IVF using the patient’s own eggs, do you recommend fresh or frozen transfers?
If the patient is in good health, with normal hormone levels and shows no risk of hyperstimulation, we usually proceed with a fresh egg transfer. If there are however medical indication that further testing, such as PGS, is warranted, or if the patient exhibits increased progesterone levels we recommend a frozen transfer.
What is the chance of having a healthy child through egg donation at age 49?
The age of the patient does not play an important role in the implantation process in egg donation cycles – the average pregnancy rate remains at around 60 to 65%. However, for patients at such an age, additional problems may arise further down the line; complications may arise during the pregnancy itself. This is why the health condition of the patient needs to be considered.
Is the donor selection process the same in every clinic, or are there differences?
Obviously, there are differences; they depend on the available donor pool, on the country a particular clinic, whether the legal framework requires genetic testing of donors, et cetera. Clinics also offer different services during the selection process; for instance, IVF Cube offers additional genetic testing of patients and donors. Some clinics also differ in their approach to donor care, for instance, we have psychologists on staff to provide support for our donors – this is also available for the recipient. The information gained during the support sessions also informs our matching process.
Partners are healthy and there is no known genetic issues in the family, do you recommend a PGT check?
It depends on the fertility history. If there have been repeated failed pregnancies, then of course we recommend genetic testing. It also depends on both partners’ age. If the female partner is above 35 years old, we suggest PGT testing, unless she’s the recipient of an egg donation – in that case, we don’t usually do testing unless there are additional indications on the male side, for example if the partner is over 50 years old.
Do you recommend a hysteroscopy and a scratch test before the implantation?
It depends on whether the tests have been performed previously – if the patient already went through a hysteroscopy or a scratch test, there is no need to repeat them before each transfer.
Will a 25x35mm myoma situated at the top of the uterus affect my chance to get pregnant?
A myoma of that size located at the top of the uterus should not affect your pregnancy.
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