Freezing eggs or embryos

Egg and embryo freezing involves daily injections for about 2 weeks to help collect mature eggs. This is known as 'stimulation'. The eggs are collected in a small procedure while you are asleep.

The injections can be started at any time in your menstrual cycle. You might have your period during stimulation but this is normal. You might also feel tired, and have bloating or discomfort in your tummy.

During 2 weeks of stimulation, you'll go to our unit 2 to 3 times for scans and sometimes blood tests, so we can check how you respond and when you're ready for us to retrieve your eggs.  

Procedure to collect your eggs

On the day of egg retrieval, you should visit the unit with another trusted person such as a family member, partner or friend. They will need to escort you home after the procedure as we use sedation. This means you will not be able to feel or remember anything during the procedure.

We usually collect your eggs through your vagina but we might offer a transabdominal retrieval (through your tummy) in some situations.

This is the final step of your fertility preservation treatment. You can usually start your planned treatment as soon as 1 day after egg retrieval.

Freezing your unfertilised eggs

Your eggs are frozen on the same day as the retrieval procedure. The fast-freezing technique we use is called vitrification. 8 to 9 out of 10 eggs are expected to survive after the freezing and thawing process.

To be used in the future, the eggs will be thawed out and injected with sperm to create embryos.

Successful pregnancy rates

The chance of a successful pregnancy depends on your age at the time eggs are collected and the total number available for treatment. In general, under the age of 35, 12 eggs would give approximately 40% to 50% chance of successful pregnancy. With 20 eggs, the chance of a successful pregnancy can increase to between 75% and 80%. 

However, there is no certain number of eggs that can guarantee a baby in the future. The number of eggs that can be collected from one stimulation depends on your ovarian reserve. Your individual chance of expected success will be discussed with you at your appointment.

Eggs can be stored for up to 55 years in the UK. Storing eggs means you can choose when to use them without needing agreement from anyone else. If you freeze embryos (eggs fertilised by a partner or donor) then you will need this person's agreement to use the embryos in the future.

Freezing your fertilised eggs (embryos)

Freezing and storing embryos is another option if you’re in a stable relationship with a partner who can produce sperm, or you have a sperm donor.

After we collect your eggs, they are mixed with the sperm of your partner or donor. The fertilised eggs (embryos) are frozen and stored. Embryos can be stored to 55 years in the UK.

If you want to use them in the future, the embryos can be thawed out and placed in your womb after taking hormone therapy. The chance of a future baby depends on your age when the embryos were frozen and the total number that were frozen. The difference in chances of live birth rates between frozen eggs and embryos is very minimal.

It's important to know that both partners must consent for using the embryos. If your current relationship ends in the future, it will not be possible to use embryos without the mutual consent of both parties involved. 

Risks of freezing eggs and embryos

It's important to be aware of the potential risks and side effects associated with this process, as with any medical procedure.

Timing and delay of cancer treatment

The process of egg freezing typically requires at least 2.5 weeks, including ovarian stimulation and egg retrieval. This might delay you starting chemotherapy slightly. Our team will work closely with your referring team to make sure any delays are as short as possible. To speed up the process, you may be referred to our service while still completing some assessments.

In some cases, chemotherapy cannot be delayed, and fertility preservation may not be possible.

Risks of ovarian stimulation

Ovarian stimulation involves daily hormone injections over approximately 2 weeks. A potential risk of this process is ovarian hyperstimulation syndrome (OHSS), which can lead to:

• increased risk of blood clots
• build up of fluid in the abdomen, chest, or both, which may need drainage
• rarely, hospitalisation for severe cases

If you have OHSS, it might cause a further delay to you starting chemotherapy. However, we make sure that the risk of OHSS is low (less than 1 in 100 people) by using a protocol that is different from the standard IVF. Your healthcare professional can explain more about this.

Risks of the egg collection procedure

We use ultrasound guidance for egg retrieval but there is a small risk of:

• infection
• bleeding
• damage to surrounding organs (such as the bladder or bowel). The risk of this is rare due to the use of advanced ultrasound technology

Oestrogen levels and cancer growth

Ovarian stimulation temporarily increases oestrogen levels. This might raise concerns if you have oestrogen-sensitive cancer. However:

• we can use anti-oestrogen medicines during stimulation to counteract this effect
• current evidence does not show a negative impact on cancer outcomes for patients with oestrogen-dependent cancers having fertility preservation

Anaesthesia risks

Egg retrieval requires having anaesthetic. It is very safe to have an anaesthetic and serious problems are uncommon. However, there are still risks involved and some people might have side effects or complications. These can include:

• allergic responses
• breathing difficulties

For large chest masses or conditions affecting the heart or airways, you will have an extra pre-assessment to make sure sedation is given safely.

Risk of cycle cancellation

We might not be able to complete your ovarian stimulation cycle if:

• your situation changes and you need to begin chemotherapy earlier than expected
• you become unwell or have a fever, and we need to cancel the cycle for your safety
• the ovaries do not respond well enough to the stimulation medicines, or the response is so low that we are unable to proceed with egg collection
• none of the eggs we have collected are suitable for freezing because they do not meet the quality criteria

We understand that this can be disappointing and frustrating. Our team will guide and support you throughout the process and discuss any further options if your cycle must be cancelled.

Emotional and psychological impact

The fertility preservation process can be emotionally challenging, particularly when combined with a cancer diagnosis. We encourage you to seek support from our counselling team, who can provide guidance and emotional care during this time.

Financial considerations

While some patients receive funding for fertility preservation through the NHS, others may need to cover part or all of the costs. If you receive NHS funding for the fertility preservation process and initial storage will need to pay for extended storage in the future.

Read more about funding for fertility preservation.

Legal information about storing eggs and embryos

Under the terms of the Human Fertilisation and Embryology Act you must give written consent about:

• the storage of your eggs or embryos
• the length of time they may be stored for
• the purposes your eggs or embryos can be used for (if you have a partner and propose to have a family with them, they can be named on the form)
• any wishes over any embryos created, or eggs stored
• what should happen to your eggs or embryo samples if you die or if you are no longer able to change or cancel your consent. You can add specific conditions of your choice

If you store embryos, your partner will need to complete the treatment and storage forms. In the future, both partners involved in the fertility preservation treatment will need to give written consent when the embryos are replaced. If one partner withdraws consent, it’s not possible for us to replace the embryos.

If you want to change your forms or for further consultations, please email IVFFertilityPreservation@gstt.nhs.uk 

You can also phone 020 7188 2300 or 020 7188 7188 extension 50426 to arrange an appointment.

It’s important to remember your priorities and wishes might change. You can withdraw or vary the terms of your consent at any time.

Funding for fertility preservation

Funding for the freezing and storage of eggs and embryos can be provided under the NHS. However, the conditions and access might be different in different parts of the country, and depends on the area where your GP is. 

The funding will be assessed once we have seen you and assessed your situation. There might be a charge for continuing the storage of eggs, embryos or ovarian tissues after a number of years.

It’s important you remain in regular contact with the unit. Please tell us of any change of address or circumstances.

If you’re not eligible for NHS funding for fertility preservation, you can still have it. However, there will be a charge for consultation, screening tests, treatment cycle, and storage. The fertility unit can let you know the prices.