Freezing female eggs can be a long process. In order to collect enough eggs (oocytes) to freeze, you have to undergo the same type of treatment as women having IVF. Drugs are used to stimulate the ovaries to produce multiple eggs. A few weeks after commencing treatment, the eggs are collected using an ultrasound-guided needle. Eggs that are mature (i.e. ready to be fertilised) can be frozen using a process called vitrification. When you wish to use the eggs, they are thawed and then fertilised using intra-cytoplasmic sperm injection (ICSI), a technique that involves injecting a single sperm into each egg. Resultant embryos are transferred to your uterus (a maximum of two at a time).
WHO MIGHT BENEFIT FROM EGG FREEZING?
- Women about to undergo chemotherapy or radiotherapy (some of these treatments can cause infertility)
- Women at risk of an early menopause
- Couples undergoing IVF treatment who have ethical or religious concerns over embryo freezing
- Women under 38 who are yet to meet the right partner but may wish to start a family in the future (requests of this nature would be considered by the team following an assessment by the Aurora Counsellor)
HOW LONG ARE EGGS STORED FOR?
Eggs can normally be stored for up to 10 years, providing that you renew your consent to storage each year by informing Aurora annually (in writing) that you require storage to continue. A form will be sent to you by registered post each year for this purpose. It is therefore most important that you keep us informed of any change of address.
In special circumstances we may be able to store eggs for more than 10 years – this depends on the reason for storage.
HOW SUCCESSFUL IS EGG FREEZING?
Survival rates for eggs following freezing depend on the quality of the eggs before freezing, but on average about 70% of the eggs frozen will survive the freeze-thaw process. Of the surviving eggs undergoing ICSI we hope about 60% will fertilise.
The use of frozen eggs is still a relatively new technique and as such it is difficult to provide any meaningful statistics regarding pregnancy rates. Success rates worldwide appear to be about 10% per attempt (rates quoted by individual clinics vary from 5% to up to 30%).
ARE THERE ANY RISKS ASSOCIATED WITH THE EGG FREEZING PROCESS?
Since the number of offspring born from frozen-thawed eggs is still relatively low it is difficult to draw any conclusions; it is likely to be several years before sufficient births have occurred to determine the true safety of the egg freezing process. However, information available indicates freezing female eggs is a relatively safe process. To date, there have been over 900 babies born worldwide as a result of egg freezing and no excess of major abnormalities has been reported. In addition, in a 3-year follow-up study of 16 children who were born as a result of frozen-thawed eggs, no developmental defects were seen.
WHAT HAPPENS TO THE STORED EGGS IF THE WOMAN DIES?
This depends on what has been written on the storage consent form (normally they would be removed from storage and allowed to perish).
Free counselling is available to anyone considering egg storage. This gives you the opportunity to discuss with an independent person your concerns regarding the storage of your eggs and their future use, including the implications for your future fertility. Support can be offered to both you and, where appropriate, your partner.
The storage of eggs is an activity licensed by the Human Fertilisation & Embryology Authority (HFEA) under the terms of the HF&E Act of Parliament (1990).
All patients wishing to store eggs must be screened for HIV, Hepatitis B and Hepatitis C.