Patient Portal: Egg Freezing
Egg freezing (oocyte cryopreservation) is a process whereby a woman has a number of eggs (oocytes) cryopreserved for future use.
The two most common reasons for women opting to freeze their eggs are
- A recent diagnosis of cancer and fertility preservation in advance of cancer treatment
- Fertility preservation as a personal choice (commonly known as social egg freezing)
An egg freezing treatment cycle involves the stimulation phase of in-vitro fertilisation (IVF) cycle. Here the eggs are collected but instead of fertilising them with sperm. The mature eggs are then cryopreserved for future use.
Initial Egg Freezing Assessment
Before egg freezing, a consultation with a fertility specialist will be arranged. This ascertains if egg freezing is a suitable option for you. It will also estimate the number of eggs that might be expected from one cycle of treatment. Some women need to undergo several cycles of treatment in order to bank enough eggs.
Controlled Ovarian Stimulation
Each ovary contains a number of follicles; these are fluid-filled sacs that each contain an immature egg or oocyte. Medications are used to encourage the growth and development of a number of mature follicles in the ovary. This is known as a controlled ovarian stimulation.
Egg collection is performed in theatre, in the fertility clinic, under sedation. Under ultrasound guidance, a thin needle is introduced to the ovary and the fluid aspirated from each follicle. This fluid should contain an egg. The mature eggs are cryopreserved and stored at Waterstone Clinic until you choose to thaw them for fertilisation
How Long does an Egg Freezing Cycle Take?
Typically, an egg freeze treatment cycle will take around 14 days. An average of four or five trans-vaginal ultrasound scans required to monitor follicle growth.
Will one Treatment Cycle be Enough?
The success of egg freezing depends on the age of the woman which will reflect the number and quality of oocytes. As a result, in order to achieve an optimum number of eggs, you may be advised to undergo more than one stimulation cycle.
Evidence shows that at least 8-10 mature eggs are required in order to give a reasonable chance (approx. 40% in ≤ 35 year olds and 20% in ≥ 36 year olds) of having a baby. However, as a woman gets older, the chance of having a baby from those eggs decreases. For example, a woman 35 years or younger who freezes 5 eggs has approximately a 15% chance of having a baby compared with a woman over 35 who has a 5% chance of having a baby from the same number of eggs.
Egg quality decreases with age and therefore women over 35 have less chances of having a baby from their frozen eggs than a younger woman. For this reason, we cannot offer egg freezing as a reasonable option for women over 38 years. In cases where a woman is seeking fertility preservation due to a cancer diagnosis we will consider egg freezing up to 40 years of age.
What Happens When I Return to use my Frozen Eggs?
Following a review consultation, a fertilisation/embryo transfer cycle will be arranged. Hormone tablets are used to prepare the lining of the womb for embryo transfer. A number of eggs will be thawed and fertilised with your partner’s, or donor, sperm using ICSI (intracytoplasmic sperm injection). The fertilized eggs will be monitored for embryo development in our laboratory. Embryo transfer will take place three or five days later. Embryo transfer involves the insertion of a fine tube (catheter) containing the embryo(s) into the uterus and the embryo(s) is carefully deposited in the endometrial cavity. Two weeks later a pregnancy test is performed.
Am I Guaranteed that by Freezing my Eggs I Can Have a Baby in the Future?
The short answer is no. Egg freezing does not give any guarantee of having a baby from those frozen eggs. It is important to know that live-birth rates from frozen eggs are lower than those achieved with an IVF cycle using fresh eggs where embryos are created.
The UK regulatory body, HFEA, quote a 14% live-birth rate from thawed and fertilised frozen eggs. However, the younger you are when you choose to freeze your eggs, the better the chance of success when you return to use them.
As egg freezing is not a guarantee of having a baby in the future, we strongly advise every woman to remain fertility aware. When the time is right for you, you should try for pregnancy without delay and not be falsely reassured by having cryopreserved eggs.
However if, in the future, you wish to become pregnant using donor sperm or you and your partner require IVF to become pregnant, then using those ‘younger’ frozen eggs may result in a higher chance of having a baby that using your fresh eggs which may be several years older. In this instance, having frozen eggs stored can be an advantage.
The risks with egg freezing are similar to those for IVF as outlined below
Ovarian Hyperstimulation Syndrome (OHSS)
This condition may develop in patients who develop a large number of follicles (more than 20) with IVF stimulation. Fluid accumulates in the ovaries (which become swollen) and in the abdominal cavity leading to abdominal swelling. If OHSS is very severe, blood clotting problems can develop which can cause strokes and even death. Treatment cycles may need to be modified or abandoned if there are concerns about severe OHSS.
Risks of Egg Collection
Pelvic infection due to egg collection is uncommon, but can occur and antibiotics will be administered on the day of egg collection to make this possibility even less likely. It is also possible for the egg collection needle to cause internal bleeding which could necessitate an operation. This complication is extremely rare in practice.
Risk of Failure to Thaw
There is a risk that a number, or all of the cryopreserved eggs will fail to survive the thawing process resulting in a lower number/no eggs available for fertilisation. This is more likely to occur in cases where women are older at the time of freezing their eggs and egg quality is poorer as a result. In women under 35 years old approximately 80% of eggs would be expected to survive the thawing process.
Eggs will be held in storage for a fixed period of one year from your egg freeze date and then for periods of 5 years thereafter (for which there will be a fee payable in advance). You will be required to contact Waterstone Clinic at the end of each five year period to confirm if you wish to continue storage for a further five years or if you wish to thaw/discard/donate your frozen eggs.
We are happy to keep the eggs in storage for as long as you may wish, as long as you maintain updated consent and contact details. Failure to contact the clinic within six weeks of the renewal date will result in the eggs being automatically thawed and discarded.
We will carry out fertilisation and embryo transfer up to the age of 49 years. You will be advised of the increasing obstetric risks associated with pregnancy and advancing age.