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Preserving fertility is done to try to help you have a family in the future.
Egg freezing is one way of doing this. It is a process where eggs are collected and frozen. These are then thawed out later to be used in fertility treatment.
The process of egg freezing
Egg freezing involves:
- Stimulation of ovaries
- Egg collection
Stimulation of ovaries
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One injection every day for around two weeks This is to stimulate egg production |
These are injections of follicle stimulating hormone. They encourage your ovaries to produce eggs A follicle is a small, fluid filled sac in the ovary that may contain an egg Before treatment starts a nurse will show you or your partner/friend how to give all the injections |
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Injections to stop the release of eggs One injection every day starting on day 6 of stimulation |
These injections keep the eggs in their follicles until it is time for egg collection Before treatment starts a nurse will show you or your partner/friend how to give all the injections |
| Vaginal ultrasound scans every 2 to 3 days to see the number and size of the follicles in the ovaries | This tells us when we should collect the eggs. It also allows us to alter your dose of medications as needed |
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| Trigger injection to make eggs mature | Once the follicles are large enough and the eggs are ready to be collected, you will take a third type of injection. This is self-administered and taken 36 hours before egg collection |
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| Egg collection | |
Egg collection
When your eggs are ready to be collected (usually after 10-12 days of ovarian stimulation) you will be given an instruction sheet by the nurses telling you exactly what you need to do.
On the day of the procedure, you will meet the anaesthetist and the theatre team as well the doctor who will be performing the procedure. They will explain what will be happening and you can ask any questions.
The procedure is called a ‘vaginal egg collection’. The eggs are collected with a needle via the wall of the vagina.
Egg collection is done at Kingston hospital in an operating theatre (a special clean room used for operations and other procedures). Depending on the number of follicles on each ovary, the procedure can take from 10 to 30 minutes.
You will be given a sedation medicine to make you very sleepy and analgesia so that you do not feel pain during the procedure. You won’t be fully asleep, but you will be very relaxed and hardly aware of what is going on. You will need to take the entire day off work.
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Once in theatre a needle will be inserted into a vein in the back of your hand. Through this you will be given a strong painkiller and strong sedation. Your legs will be placed in stirrups |
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An ultrasound probe with needle attached is used to collect the eggs from the ovaries. The probe is inserted into your vagina and the needle is then guided through the wall of the vagina into the two ovaries in turn. The needle is used to puncture and drain every follicle |
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The fluid from each follicle is collected in a test tube and placed in an incubator. You will need a relative, partner of friend to take the incubator containing the fluid to Kings Fertility Clinic immediately after the egg collection. At Kings Fertility the embryologists will carefully examine the fluid and freeze all the suitable eggs that are collected |
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Following the egg collection, you will rest in the theatre recovery area for an hour and a half or so until you feel able to go home. You will still feel drowsy so your relative, partner or a friend must take you home once they return from Kings Fertility. |
Sometimes you may get fewer eggs collected than expected. Very occasionally we do not collect any eggs. This may be for a number of reasons.
- The ovaries may not have responded well to the hormone injections.
- Sometimes many follicles develop but without mature eggs.
- Although the doctor will drain every follicle possible, not all contain an egg.
- Very occasionally it is not possible to reach the ovaries.
Risks of egg collection
Although egg collection is a common procedure there are some risks.
Bleeding
The needle used to collect the eggs might accidentally puncture a blood vessel. This can cause bleeding either into the vagina or into the abdomen.
Bleeding into the vagina is quite common and easy to treat. We simply press on the bleeding point for a few minutes until the bleeding stops or we give you medication that helps stop bleeding.
Bleeding internally is very rare but may require admission to hospital. You would then have an operation with general anaesthetic to stop the bleeding.
Puncture
The needle might accidentally puncture the bladder or the bowel or any other organs in the pelvis.
This may cause leakage of urine into the surrounding tissues, bleeding into the bladder, or leakage of bowel contents into the abdomen.
These complications might settle down without treatment but could cause pain and infection.
Infection
The needle might cause an infection.
It is impossible to make the vagina free from germs. Therefore, there is a small risk that the needle might carry germs from the vagina into your abdomen. In some people this might cause an infection, which can lead to an abscess.
It can take several weeks for an infection to show. It might need admission to hospital and an operation to drain the abscess. The serious complications described above are rare and may occur once in every thousand procedures performed in the unit.
After egg collection
It is common to have some crampy, period-like pain and light bleeding for around 24 to 72 hours after egg collection. To relieve this pain, you can take paracetamol or similar pain medicine that can be bought without prescription.
Urgent contact
Contact Kingston ACU nurses immediately if you feel particularly unwell, with sharp pain, fainting or a fever.
During normal working hours:
- 020 8934 3155.
Outside of normal working hours:
- a nurse is on-call and can be contacted on the emergency number provided on the ACU voicemail message.
The bleeding should get lighter over the first few days. Use sanitary towels not tampons. This is to reduce the risk of infection.
Contact us on 020 8934 3155 if the bleeding gets heavier or just doesn’t stop.
Expect to have your period within the next two weeks. Tampons can be used for this.
Around one week after egg collection the ACU nurses will contact you to check how you are following the egg collection procedure
Recovery
The egg collection is a medical procedure that involves sedation.
It is important that you do not drive for the rest of the day. You must be driven home and should not take public transport.
Due to the sedation, a responsible adult must go home with you. You must not drive or operate machinery for 24 hours. Following your sedated procedure, we recommend you take the next 24 hours off from work.
Egg storage at Kings Fertility
Your eggs will be frozen, ready for fertility treatments later. This is called ‘egg vitrification’ or ‘cryopreservation’.
Only mature eggs can be frozen. Not all the eggs collected will be mature.
The eggs have some water removed and are then frozen so quickly that ice crystals do not form.
You will be told how many eggs have been collected and how many frozen and stored for future use by the embryologists at Kings Fertility Clinic on the afternoon of your egg collection.
When you are ready to use the eggs, you will have to give us written permission to thaw them.
We will also help you decide how many eggs you would like thawed.
Once thawed, embryo creation is attempted using ICSI (Intra Cytoplasmic Sperm Injection). This is the injection of one sperm into each egg. Fertilised eggs, then known as embryos, are cultured for 5 days. Then a maximum of two embryos are transferred into the womb. Any spare good-quality embryos remaining after transfer can be frozen and stored for future use.
The law permits you to store frozen eggs (or embryos created using your eggs) for up to 55 years.
You must give written permission to store your eggs (also called ‘consent to storage’). You can give permission for up to 10 years at a time. There is also a yearly storage charge.
Before your consent comes to an end, you will be contacted by the laboratory storing your eggs. You will be asked if you wish to renew your consent to storage.
When considering how long to store for, there are things to consider and discuss with us:
- how far in the future might you want to, or be able to, use stored eggs
- the costs of storing.
We do recommend that embryos are created and used in treatment before you reach the age of 50. Please note that embryos can only be stored if the sperm provider has also given consent.
Contact us or Kings Fertility Clinic at any stage if you want to change your storage period or withdraw your consent to storage. At that time, you will be offered further counselling, given relevant information, and asked to complete another consent form.
You must tell us and Kings Fertility Clinic if your contact details change because we will need to contact you about your consent to storage. If Kings Fertility are unable to contact you when your consent to storage ends, your eggs and/or embryos will have to be disposed of. You will be given more information on this when you complete your consent forms.
International follow-up studies of children born after egg freezing have not revealed any increased risk of problems during pregnancy or increased risk of birth defects.
Research is still being done to see if freezing eggs for a long time causes any damage. There is not yet enough evidence to say for sure either way.
This needs re-working
Studies have shown that success rates with frozen eggs are as good as with fresh eggs. However, we do not yet know how these rates apply to women who to choose to freeze their eggs for non-medical reasons. This is because many women have returned to use their eggs yet.
Although there is a lack of local data, research from Spain of 137 out of 1468 women who returned to use their frozen eggs, reported a cumulative pregnancy rate per patient of almost 60%. Another study from Sweden in 2019 of 38 patients from 254 women who had frozen their eggs, showed a cumulative pregnancy rate of 63% for women 36–37 years of age at egg freezing; and 26% for women 38–39 years of age at freezing.
There were no births from women who froze their eggs when they were 40 years old and over. We do not generally recommend egg freezing to women over 40 as results are poor.
Needs re-working
Another important issue to consider is how many eggs to freeze and store to maximise the chance of a live birth. It is difficult to determine the ideal number of eggs to freeze to offer the best chance to conceive; since successful pregnancy following fertilisation of the eggs depends on many factors, including maternal age and health and paternal health and sperm quality. No number of eggs can offer a guarantee for future conception. Chances are better if more than 10 eggs are frozen. Two American prediction models, based on IVF/ICSI-treatments, estimate that approximately 20 eggs are required, to have around 75% likelihood of achieving at least one child provided that the woman is younger than 38 years. The models also show that the chance of success is highly age-dependent and confirm that attempting fertility preservation in women over 40 years is unlikely to succeed. Cryopreservation of too few oocytes would limit the possibility of success. Some women will therefore require more than one round of fertility preservation to produce a reasonable number of eggs to give a good chance to conceive in the future.
More information
HFEA (Human Fertilisation and Embryology Association) has more information on egg freezing.
Contact information
Kingston Assisted Conception Unit nurses