Egg freezing

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. The length of storage could be up to 55 years. You can also choose to store your embryos for up to 55 years and used in a future frozen embryo transfer (FET) treatment cycle.

What is egg freezing?

Egg freezing – also called oocyte cryopreservation – helps to increase the chance of having a baby at an older age as human egg quality is strongly dependent on a woman’s age. Therefore, trying to secure some eggs at a younger age, can enhance the chance of conception later in life when natural chances drop very significantly. This method allows you to collect eggs from the ovaries and freezes them unfertilised before being stored for later use

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.

Others may wish to preserve their eggs due to cancer treatment or radiation therapy. And there can be religious reasons to undergo egg freezing as an alternative to embryo freezing.

Egg freezing age limit

The optimal age range for egg freezing is under 35. However, if you have thought about it at a much later age, we will be happy to assess you and advise what would be the best option for you depending on multiple factors.

How does egg freezing work?

You will typically have 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 personal egg quantity
  • an ultrasound to assess how your ovaries are working
  • screening for infectious diseases like hepatitis B, hepatitis C and HIV to allow safe storage of the eggs.

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 which stimulate the ovaries to grow multiple eggs, rather than a single egg per month (as in the natural cycle). You also would need to take 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 attend to have vaginal/abdominal ultrasound scans to monitor the 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 at a clinic. You will be given a sedative to make you comfortable for the procedure, called ‘transvaginal egg collection’. This is where an ultrasound probe is inserted into the vagina, allowing the 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 – our own research has shown the number of eggs required to have a more optimal 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 collected, our embryologists will assess and determine which eggs can be frozen. As 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 sperm. They can then be implanted in your uterus or the uterus of a gestational carrier.

How long does the process of egg freezing take?

Stimulation for egg freezing usually takes on average 14 (11-16) days – this period of time accounts for the egg freezing cycle, which will begin when you start your period and contact your clinic to let them know you are ready to begin treatment. Between 11 and 16 days of hormone injections are usually required.

There are several steps to take prior to 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.

Does the egg freezing process have any risks?

All types of medical treatments and procedures have some risks. But overall the risks for egg freezing process are quit small in modern practice. We will speak with you about the risks involved. Possible risks associated with egg/embryo freezing  process include:

  • ovarian hyperstimulation syndrome (OHSS). This a condition that is associated with increased risk of blood clots and accumulation of fluid in the tummy and very rarely in the chest after the egg collection. However, we take several steps in egg/embryo freeze process that are different to those in IVF with fresh embryo transfer that makes the risk of OHSS extremely low (under 1%)
  • pelvic infection can rarely follow an egg collection and, rarely, an abscess might develop. We try to make sure this does not happen by performing the collection under clean conditions and giving antibiotics to women who are at higher risk of infection. The reported incidence of pelvic infection in literature is under 1%
  • poor ovarian response, and therefore having no eggs to freeze. This risk is increased in older patients with low egg reserve. Our team will be able to guide you based on your individualised circumstances

Egg freezing success rates

“Our own 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,” explains Dr Kopeika.

Women under 35 who freeze 15 to 20 eggs have approximately a 75% chance of giving birth to at least one baby. However, we welcome women older than 35 and who are still ovulating to come and see us too. Every patient is unique, and we can explore the best options to help them get pregnant in future.”


For more information on the costs associated with egg freezing and storage, please visit our fertility services pricing page.

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