ELECTIVE EGG FREEZING
What is egg freezing?
Egg freezing – or mature oocyte cryopreservation, as its known medically – is a fertility treatment. If you choose to freeze your eggs now, your chances of falling pregnant later relate to your current age. That is, the age at which your eggs were frozen. This is reassuring because the chance of pregnancy declines as egg quality declines as women get older. So if you freeze your eggs now and want to use them later, your chances of conceiving will be higher.
Who might consider egg freezing?
Egg freezing is becoming an increasingly popular choice. There are a number of reasons why women may choose to freeze their unfertilised eggs.
- Some women freeze their eggs because they know they want to become a mother but are not currently ready to take that leap. Then there are those who are unsure if they want to have a baby at all. These women may undergo egg freezing ‘just in case’ they decide they want a baby in the future.
- There are also women who may freeze their eggs for medical reasons. They may choose to freeze their eggs before embarking on medications or therapies that may impact their fertility. Women with medical conditions that may impact fertility, such as an autoimmune disease, may also choose to undergo egg freezing. Egg freezing may also be performed before In Vitro Fertilization (IVF).
What is the process of egg freezing?
During a regular cycle, a woman releases an average of one egg at the time of ovulation. If you wish to undergo egg freezing, it is best to have multiple eggs available for this process. In order to produce more eggs, your doctor will give you medication to signal your ovaries to produce more eggs.
The amount of mature eggs produced per cycle of stimulation varies from woman to woman. While some women can produce more than 20 eggs in one cycle, this is not always the case. Many women aged 35 and under may require more than one treatment cycle to produce their goal number of mature eggs. The egg-stimulating hormone medication is self-administered via daily injection using a small needle for approximately 10 days. Your doctor will teach you how to give yourself these hormone injections.
The stimulating hormone injections may make you feel a little bloated. In rare cases, you may experience a phenomenon known as ‘ovarian hyperstimulation syndrome’ (OHSS). Most cases of OHSS are mild. Symptoms may include bloating, diarrhoea, nausea and slight weight gain. If you are concerned you may have OHSS, please talk to your doctor.
You are unlikely to experience other side effects from hormone injections to stimulate eggs for egg freezing. You can continue with life as normal during this time.
Once your body has grown the eggs, your doctor can ‘harvest’ or retrieve them for egg freezing. That is done via a simple procedure as an outpatient. It is usually performed under light general anaesthetic, or with sedation. This procedure involves an ultrasound-guided probe being inserted into the vagina. Within the probe, there is a needle that can collect your eggs.
The risks of egg retrieval include a very small risk of infection. There is also a very small risk of damage to structures around the ovaries, such as bladder, bowel and blood vessels.
Once those eggs have been collected, they can be examined before being frozen in liquid nitrogen. The process of egg freezing is also known as ‘vitrification’.
How do I know how many eggs I have left?
To determine how many eggs you have left, your doctor may recommend having some tests.
Firstly, your doctor may order a blood test can check your Anti-Mullerian Hormone (AMH) levels. Your AMH levels can indicate your ‘ovarian reserve’ or ovarian function, which gives an idea of how many eggs you have left. Your doctor may also order an ultrasound test.
What is the success rate of egg freezing?
The success rate of egg freezing can be difficult to predict. That said, many women have gone on to have babies from using their frozen eggs. In women aged 35 and under, one stimulated cycle results, on average, in the collection of around 10 – 12 eggs. Of those, around 7 – 9 eggs are likely to be suitable for egg freezing.
On average, approximately:
- 90% of frozen eggs survive the process of thawing
- 50-80% of them then survive fertilisation (being mixed with sperm)
- 80 – 90% of them develop into embryos.
Each single embryo then has a 20 – 35% chance of developing into a pregnancy, which can lead to a live birth. Freezing 20 – 30 eggs gives you around an 80% chance of having a live birth. For more details on the chances of having a baby after egg freezing, talk to your doctor.
What comes after egg freezing?
Once your eggs are frozen, you can relax in the knowledge they will not age while in storage. That means your chances of falling pregnant relates to the age you were when you underwent egg freezing. It is also reassuring to know that eggs can stay frozen for many years without significantly deteriorating.
If you would like to then try to have a baby, your eggs can be thawed. Those thawed eggs can then be fertilised with sperm in a process known as Intra-Cytoplasmic Sperm Injection (ICSI). When that process results in an embryo, it can be transferred back into your uterus to hopefully achieve a pregnancy.
How will my eggs be used in the future?
Once you store your frozen eggs, you are in control over what happens to them. If you would like to use them to try for a baby, your eggs can be thawed. If you no longer want to continue freezing your eggs, there are a number of options available. Some women choose to discard their frozen eggs. Others prefer to donate their eggs to people who are hoping to fall pregnant. Then there are those that select to donate their unused eggs to medical science. For more information on your options, please talk to your fertility specialist.
How many eggs should I store to achieve a pregnancy?
For a woman aged under 35, it is ideal to store around 20 – 30 frozen mature eggs (oocytes). Freezing that number of eggs provides an 80% chance of live birth.
If possible, women older than 35 should aim to freeze more than 20-30 eggs. That’s because women older than 35 are more likely to face issues with the quality of their eggs.
Many women may need to undergo more than one IVF stimulation cycle to retrieve this number of eggs. It is important to understand that freezing your eggs does not guarantee that pregnancy will be achieved with those eggs.
How much does egg freezing cost?
The cost of egg freezing can vary at different clinics. Please speak to your fertility specialist about how much this procedure may cost.
Egg freezing for cancer patients
Unfortunately, some treatments for cancer can affect your future fertility. That is why, before undergoing certain procedures, your doctor may recommend egg freezing. If you are considering undergoing egg freezing for this purpose, please speak to your fertility specialist.
ANZSREI consensus statement on elective oocyte cryopreservation
One in six Australian women and couples suffer infertility. A rising proportion relates to advanced maternal age, associated with poorer oocyte qual- ity and in vitro fertilisation (IVF) outcomes. Internationally, oocyte cryopreservation technology applied to oocytes vitrified before 35 years provides similar live-birth statistics compared to IVF treatment using fresh oocytes…