If you want to have a child in the future, but have not had the opportunity during your most fertile years, then freezing your eggs for use when you’re ready to start a family may offer you opportunities to conceive in the future.
A woman is most fertile in her 20s and early 30s when her ovaries still contain a large number of healthy eggs. As a woman ages, the quality and quantity of her eggs declines. For the 10 to 15 years before menopause, despite having regular monthly periods, ovarian function declines. This is especially so for women in their 40s who are unlikely to produce a healthy pregnancy.
What is the egg freezing process?
Egg freezing is a method of storing a woman’s unfertilised eggs, with a view to them being used in the future. It may be seen as a way of preserving potential fertility, in women who are not in a position to currently become pregnant or those requiring preservation of their fertility for medical reasons.
When the woman is ready to use her eggs, they are thawed and then fertilised with sperm. Depending on your circumstances, you may have enough time before starting your chemotherapy or radiotherapy to have more than one cycle of hormone stimulation and egg retrieval. This ensures that you have a reasonable number of eggs to freeze and therefore an increased chance of a future pregnancy.
To obtain eggs for freezing, a woman undergoes hormonal stimulation over 10–12 days which stimulates a group of eggs (usually 10–15) to mature. There are a variety of stimulation techniques for this and your fertility specialist will decide, in discussion with you, which is the most appropriate for you.
The stimulation medications are usually self-administered by an injection using a tiny needle under the skin and are very easy to administer. Patients are taught how to do this in an instructive introductory session with a Melbourne IVF fertility nurse. The injections may make the woman feel a little bloated, but she can carry out all normal activities up until the day of the egg retrieval.
Procedure to remove the eggs
The eggs are removed from the ovaries using an ultrasound guided probe whilst the patient is asleep under sedation. Attached to the ultrasound probe is a needle guide. The fine needle passes through the vaginal wall into the ovary and draws the fluid (and egg) from the ovary.
The entire procedure takes approximately 10-15 minutes and patients can go home about one hour after the procedure and are advised to rest quietly for the rest of the day. It’s often suggested to take at least half the following day off work and someone will need to pick you up after the procedure as you may feel tired or groggy.
Egg freezing procedure
The eggs undergo a freezing procedure known as vitrification in our IVF laboratory. This process involves immersing each egg in a series of special fluid solutions to protect its cellular structure, followed by storage in freezing tanks of liquid nitrogen. Eggs may be stored for many years.
Who might benefit from egg freezing?
As women age they have fewer eggs and freezing therefore, becomes less beneficial as only a small number of eggs may be obtained in the cycle. For this reason, egg freezing for non-medical reasons is not usually recommended for women over the age of 38, unless blood tests indicate a very high ovarian reserve.
The expected success of the procedure can be ascertained from an initial assessment of the ovarian reserve, via an anti mullerian hormone (AMH) test and an ultrasound. The AMH test can provide an insight into the remaining quantity of eggs and number of fertile years a woman has remaining, although it does not provide information about the quality of the eggs.
Success rates for egg freezing
As the technique for egg freezing is relatively new, it is not possible to give precise figures for the chance of pregnancy after freezing. We would expect:
- A stimulated cycle would result in the collection of 10-12 eggs (10-20 eggs in women younger than 35)
- Approximately 85-90% of eggs would survive the freeze and thaw process
Once an egg survives the freeze and thaw process, we would expect it to behave like a fresh egg, offering:
- Approximately 50-70% of eggs would fertilise
- Approximately 90% of fertilised eggs develop into embryos on day two but only 30-40% develop onto day five (blastocyst embryos)
- A single embryo would have a 25-40% chance of developing into a pregnancy depending on a woman’s age
Our experience at Melbourne IVF suggests that 15-20 eggs are required to generate a single pregnancy. The number of eggs expected to be required to produce a pregnancy is reported to be higher in other units, with some suggesting 30 or more eggs. Your fertility specialist will discuss how many eggs they recommend you freeze depending on your individual circumstances.
The woman’s age when her eggs are frozen has an important effect on the chance of pregnancy. The younger the woman, the better chance of producing more eggs to freeze. Egg freezing in women over the age of 38 years would be expected to have a lower chance of pregnancy.
Egg freezing costs
In Australia Medicare subsidies apply only to medical egg freezing.
For an explanation of the costs associated with social egg freezing, please call our Community Liaison Administrator on 1800 111 483 or email us.
You need to be referred by your local GP or a medical practitioner to a Melbourne IVF fertility specialist for egg freezing.
Your Melbourne IVF fertility specialist will take a medical history, arrange any necessary investigations including blood tests and ultrasound assessment of the ovaries, as well as arrange a counselling referral if appropriate.