Egg freezing and storage

As part of our private fertility service we offer egg, sperm and embryo freezing and storage. Our team of renowned fertility experts at the Assisted Conception Unit place the highest importance on patient safety throughout their fertility treatment journey.

At our dedicated storage facility, your eggs are stored using a state-of-the-art freezing technique called vitrification. It allows us to freeze and subsequently thaw your samples for your future use with the same success rates as using fresh samples.

Your gametes could be stored for up to 55 years to be used in a future in assisted conception techniques such as a frozen embryo transfer (FET) treatment cycle.

What is egg freezing?

Human egg quality is strongly dependent on a woman’s age. Egg freezing – also called oocyte cryopreservation – helps to increase the chance of having a baby at an older age.

Trying to secure some eggs at a younger age can give you peace of mind knowing you have a greater chance of conception later in life. This method allows you to collect eggs from the ovaries and freeze them, unfertilised, before being stored for later use.

Who can use egg freezing?

There are many reasons why women may choose to freeze their eggs. Some women may feel that it isn’t the right time to start a family, and they’d like to preserve their younger eggs for future use. For some people who haven’t met a suitable partner, egg freezing offers you the opportunity of preserving your fertility as opposed to other methods like embryo freezing.

Others may wish to preserve their eggs due to medical treatment like chemotherapy or radiation therapy.

Egg freezing age limit

The optimal age range for egg freezing is under 35. However if you have thought about it at a later age our specialists will be happy to assess your fertility potential and advise on the options available.

Preparing for egg freezing

Before you undergo fertility testing or treatment, you must have a consultation with our fertility specialists. We understand that starting a family can be exciting, but it can also impact your emotional wellbeing. A consultation helps you prepare for this new stage in your life and gives you the opportunity to ask any questions you may have.

After meeting with our specialists and confirming you are eligible, you will typically undergo some tests before the start of the egg freezing process. These may include:

• egg reserve testing – done by a blood test to check the estimate of your egg quantity
• an ultrasound to assess how your ovaries are working
• female hormone profile blood tests (FSH, LH, E2, TSH)
• screening for infectious diseases like hepatitis B, hepatitis C and HIV to allow safe storage of the eggs

Find out more about our full range of fertility tests.

How does egg freezing work?

Egg freezing can be broken down into three stages:

1. ovarian stimulation
2. egg retrieval
3. egg freezing

Ovarian stimulation

Ovarian stimulation requires you to take synthetic or naturally extracted hormones. These stimulate the ovaries to grow multiple eggs rather than a single egg per month as per the natural cycle. You also would need to take an injection that prevents ovulation (the release of a mature egg from the ovary).

During this treatment you may need blood tests that measure your response to the medications. You will have vaginal/abdominal ultrasound scans to monitor your response and development of follicles (the sacs of fluid in the ovaries in which eggs mature).

Egg retrieval

This takes place when the follicles are ready – usually after 11 to 16 days – and will be done in hospital. You will be given a sedative to make you comfortable for the procedure, called transvaginal egg collection.

During transvaginal egg collection an ultrasound probe is inserted into your vagina allowing follicles to be identified. A needle will then be guided into a follicle via your vagina and a connected suction device can remove the egg.

This process can be repeated to remove multiple eggs – research has shown the number of eggs required to have a higher chance of live birth is 15 if you have this process under the age of 35. A larger number of eggs may be required if the process is done at a later age. However there is no certain number of eggs that can guarantee a baby in the future.

Egg freezing

Egg freezing will be done soon after the unfertilised eggs have been collected. Once eggs are collected, our embryologists will assess and determine which eggs can be frozen. Some of the collected eggs may naturally not be mature enough to be stored and would need to be discarded.

The mature eggs are cooled to temperatures -198°C, preserving them for future use. Vitrification – a process used to protect tissue from freezing by stopping ice crystals from forming during the freezing process – assists in egg freezing, which is typically more delicate than embryo freezing.

Following the procedure you will usually be able to resume your everyday activities within a day or two. When you wish to use the frozen eggs they will be thawed and fertilised with your chosen sperm. They can then be implanted in your uterus or the uterus of a gestational surrogate.

How long does egg freezing take?

Stimulation for egg freezing usually takes on average 14 days – this period accounts for the egg freezing cycle which will begin when your period has started and you let our fertility team know you are ready to begin treatment. Between 11 and 16 days of hormone injections are usually required.

There are several steps to take before the egg freezing cycle, such as attending an appointment that guides you on administering medication, gaining an understanding of your cycle schedule and signing the required consent forms. How long these steps take to complete will depend on your availability.

Egg freezing success rates

Our research suggests that higher pregnancy rates are associated with eggs frozen at younger ages in comparison to older ages. It is known that the best time to freeze eggs is before the age of 35.

Women under 35 who freeze 15 to 20 eggs have approximately a 75% chance of giving birth to at least one baby. We do welcome women older than thirty-five who are still ovulating on a case by case basis. Every patient is unique and we can explore the best options to help you get pregnant in future.

Risks of freezing your eggs

All types of medical treatments and procedures have some risks. But overall, the risks for the egg freezing process are quite small in modern practice. Your expert consultant will speak with you about all the risks involved. Risks associated with the egg/embryo freezing process include:

• ovarian hyperstimulation syndrome (OHSS). This is a condition that is associated with an increased risk of blood clots and accumulation of fluid in the tummy and very rarely in the chest after the egg collection. We take several steps in the egg/embryo freeze process making the risk of OHSS extremely low (under 1%)
• pelvic infection can rarely follow an egg collection and in some very rare cases an abscess might develop. We perform all medical interventions under sterile conditions and will give you antibiotics if you are at higher risk of infection. The reported incidence of pelvic infection in literature is under 1%
• poor ovarian response and in some cases having no eggs to freeze. This risk is increased in older patients with low egg reserves. Our team will be able to guide you based on your individualised circumstances