Egg freezing – also known as egg vitrification or cryopreservation – refers to the process whereby eggs are rapidly frozen to be used for assisted conception treatments at a later date.
The process starts similar to IVF treatment, with a course of injections to stimulate the ovaries so several eggs can be collected, followed by the normal IVF egg collection procedure. Once the eggs are collected, we use the latest cryopreservation techniques known as vitrification to freeze and store your eggs for future use.
Until recently slow rate egg freezing was used with the limitation that ice crystals can form within the egg that can destroy the cell’s structure. To overcome this, egg vitrification involves dehydrating the eggs using a specialised freezing technique, which freezes eggs so quickly that ice crystals are prevented from forming.
The use of vitrification technology to freeze eggs offers a new option for:
- Cancer patients looking to preserve their fertility prior to surgery, chemo or radiotherapy. Embryo freezing is still a more successful technique for fertility preservation because embryos have higher chances of surviving and implanting, but egg vitrification is being used for young or single cancer patients
- Women at risk of early menopause can choose to store eggs before the onset of menopause
- Women who are due to undergo medical or surgical procedures that could make them infertile
Whether you are wanting to freeze your eggs for medical reasons or non-medical social reasons – eg financial, lifestyle or relationship factors – we can help you keep your options open.
FAQs:
How long does it take to freeze your eggs?
A cycle of egg freezing usually takes 2-3 weeks from when one has to start taking medication and be monitored, to the end of the process which is the egg collection procedure itself. This is usually preceded by a ‘work-up phase’, such as a consultation, blood tests and ultrasound scan. Once the egg freezing cycle commences, each monitoring visit lasts typically 20-30mins, and several are required during this timeframe. The egg collection procedure in itself usually lasts 20-30 minutes, and after one to two hours of recovery the person can go home. There might be a small amount of spotting from the vagina, and occasionally discomfort over the lower abdomen. However, simple pain relief medication (such as paracetamol or ibuprofen) is usually adequate in controlling it. One should be able to return to normal activities by the next day, and the period should arrive within the next two weeks. After that, the body should be back to normal and all the effects of the hormones should have passed.
How does the process work?
The egg freezing process is similar to a cycle of IVF, except that the fertilisation of the eggs with sperm and subsequent embryo transfer back in to the uterus happens at a date in the future. Initially a course of daily injections (usually two different medications, or sometimes three) are self-administered. These aim to stimulate the ovaries to produce a number of growing follicles (fluid-filled sacs within which the eggs reside) and also to control the ovulation so that these eggs can be collected. The daily injections continue for a couple of weeks, known as the ‘stimulation phase’. During this phase, ultrasound scans are performed every few days looking at the ovaries in order to monitor the progress of the growing follicles and occasionally a blood test to check hormone levels. Once the follicles have grown sufficiently, and to a size where it is expected that a mature egg will be retrieved, a final ‘maturation injection’ is given, followed by the egg collection procedure two days later.
The collection procedure itself is carried out under anaesthetic (usually sedation) which is given by a consultant anaesthetist. This ensures that the procedure is comfortable. Using ultrasound guidance, a needle is passed through the vaginal wall, then into the ovaries, and into each of the follicles. Fluid from within the follicles is drawn out and taken to the laboratory. An embryologist will look at this under a microscope in order to retrieve the eggs. The eggs are then checked for maturity and frozen within a few hours after the procedure. They’re frozen using a ‘fast-freezing’ process called vitrification and stored in specialised cryotanks. The tanks are constantly monitored electronically and maintained and the eggs can remain there for as long as they are required (up to 55 years by law).
What is the average success rate for frozen eggs?
Success rates vary dramatically based on multiple factors, including the individual’s age at the time of egg collection (the younger the eggs, the higher the success rate) and their general health. If the eggs are frozen at a clinically optimum age then the chances of success will be higher. However, it should be noted that obstetric (pregnancy) complications increase with one’s age. Overall, the absolute chance of an egg successfully resulting in a baby can vary from as low as less than 1% per egg to 5-6% per egg. Data from the HFEA show that as an average across all age groups, 2% of all thawed eggs ended up as pregnancies and 0.7% resulted in live births. The average number of eggs frozen per patient is eight. According to the same data, if an individual freezes their eggs before the age of 35 years, on average there is a 27% chance of these leading to a birth, compared to 13% if someone froze their eggs when they were over the age of 35. The most common age for an individual to freeze their eggs in the UK is 38 years.
How many eggs should be frozen?
The number of eggs needed to be frozen depends on the age of the individual at the time of freezing their eggs, how many children they would like to have, and what ‘probability of success’ they would like to have.
This is a complex calculation. A lot of the quoted numbers are based on mathematical modelling and relatively small studies – as opposed to data for fresh eggs which is much more robust as these are based on international data from hundreds of thousands of cycles.
In many cases, the quoted egg numbers can never be collected (for example if the ovarian reserve is low), or the quoted success rates can never be achieved (for example if the woman is older at the time of freezing her eggs, if there are other fertility issues such as uterine and sperm problems etc).
Nevertheless, some rough statistics frequently referred to are as follows:
A woman under 35 years needs roughly 10-12 eggs frozen for a 50% chance of having a baby or 20-30 eggs frozen for an 85% chance. For women over 36 years the above statistics start to gradually drop. Overall, the numbers are half for women who are over 36 years compared to under 35 years. However, not all ages over 36 years are the same, and certainly for those over the age of 40 years the statistics become very low. Also, the ability to retrieve these numbers of eggs drops with age. So although older women require more eggs for the same success rate, the number of eggs that can be retrieved per cycle also drops. We can advise on your personal situation when you visit.
Why do women freeze their eggs?
There are many reasons why someone might decide to freeze their eggs and each decision is extremely personal and unique. One of the most common reasons is that an individual isn’t ready to have children yet or hasn’t met the right person to have them with, but knows they want children one day. Another common reason is if someone is scheduled to receive medical treatments that affect fertility, like chemotherapy or ovarian surgery, and freezing eggs helps to preserve the chance of having children down the line. Others may be inclined to freeze their eggs because they haven’t decided on whether or not they want children, but want to remove any feeling of time pressure from their decision-making process.
What should one consider when deciding if egg freezing is right for them?
Just because one can store eggs it does not mean it is also the right decision for them. Egg freezing is a medical process and has some inherent risks associated with it. For some, these risks are higher than others and a personalised risk-benefit assessment should be undertaken.
Egg freezing can also lull someone into a sense of security, when in fact there is no guarantee of future success from one’s stored eggs.
Finally, a significant proportion of those storing eggs may never in fact end up using them in the future. However, we find that many people have difficulty in verbalising that they wish to dispose of their unused stored eggs or embryos and this decision can cause an undue amount of psychological distress.
How long can eggs be stored for?
You can store your eggs for a period of up to 55 years; you will need to actively renew your consent every ten years and you will be contacted about this accordingly.
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