As women become older, their chances of getting pregnant begin to decrease. This decline starts after the mid-thirties and becomes even more pronounced over the age of 40. Freezing your eggs at a stage in your life when the ovaries are capable of producing high quality eggs is therefore a sensible option for fertility treatment in future years.
Modern technology has allowed us to see a significant improvement in the egg freezing technique, raising the awareness of its value significantly. Those who could potentially benefit include:
Additionally, as societal norms change, particularly in global cities such as London, many women postpone having children for several reasons, including:
Women who can benefit from social egg freezing are those who are at the given moment unready for parenthood, but would like to have the best chance of becoming pregnant at the right time for them.
Preparation of the patient for egg freezing and storage is no different to that for IVF. First the woman is assessed for ovarian reserve through a blood test for Anti Mullerian Hormone (AMH) and a transvaginal ultrasound scan to assess antral follicle count. This will help to choose an appropriate protocol and drug dose for ovarian stimulation. After 10 – 12 days of injections, the eggs are matured by a final trigger injection and collected 36 hours later. Egg retrieval is achieved by a needle going via the vagina into the ovarian follicles to aspirate the eggs under ultrasound guidance. The procedure is performed under intravenous sedation.
Only mature eggs are cryo preserved (frozen) using the vitrification technique with dehydro cryoprotectants. To use the eggs later in life, they are thawed and injected with the sperm with the Intracytoplasmic Sperm Injection (ICSI) technique. The resulting embryos are replaced into the woman’s uterus a few days later as in fresh IVF.
According to the HFEA Code of Practice, you may store your eggs for up to 10 years. However this period can be extended under special circumstances for up to a maximum of 55 years. You should consult your fertility clinic if you need this.
The HFEA statistics of IVF cycles in 2006 show that 30.7% of the total of 39,783 cycles performed, were undertaken by women aged 38 or over. The average live birth rate in that year for women aged 38 was 17.9% per cycle. This reduces to 12.5% for women aged 40 and 6.6% for those aged 42.
The UK has the highest European age of first birth at the age of nearly 30. The latest projection estimates that 22% of women born in 1990 or later will remain childless, while 15% of mothers will have their first child at the age of 35 or over. There is a 6% permanent childlessness when women delay pregnancy attempts until the age of 30, 14% when those attempts begin at 35 and 35% when they begin at 40.
Clinicians have a duty to inform patients that a woman aged 40 or above is more likely to achieve a healthy pregnancy using embryos that were created in her mid-30s than using fresh embryos over 40 years old.
The emerging evidence base in regards to the efficacy and safety of oocyte cryopreservation is overwhelming. Survival rates, fertilisation rates and implantation rates of young cryopreserved oocytes, fertilised using ICSI are comparable with those of matched fresh oocytes.
Evidence to date indicates no increase in chromosomal abnormalities, birth defects or developmental defects of children conceived from frozen eggs. On the contrary, using eggs frozen at a younger age can reduce the risk of miscarriage and the risk of genetic and chromosomal abnormalities in children born to women over the age of 35.
The success rates of frozen / thawed eggs are similar to those of fresh eggs and there are no increased risks for the mother or the baby. There might actually be benefits of lower miscarriage rate and chromosomal abnormalities due to the younger age of the eggs at the time of retrieval.
Reported clinical pregnancy rates at 35- 60 years are realistic for freezing eggs at a young age. The expected success rate in terms of women aged 30 or 35 is 24% and 18% respectively, per six vitrified – warmed oocytes.
It is claimed that you might need 10 frozen eggs to have a live birth. This number of eggs can be produced in one or more ovarian stimulation cycle based on your age and your ovarian reserve. Mathematical calculation indicates the following expected live birth rate:
|Age||Live Birth Rate based on 10 Frozen eggs||Live Birth Rate based on 6 Frozen eggs||Average No. frozen eggs in one cycle||Live Birth Rate per egg freezing cycle|
Unfortunately the average age of women freezing their eggs is currently around the 37-38 year mark, which does not result in high success rates. We should encourage younger women in their late twenties and early thirties to freeze their eggs if they are considering delaying parenthood for whatever reason. There is a lack of awareness in regards to the fertility potential timeline (the biological clock) and the availability of egg freezing.
Of course, as the success of egg freezing is not guaranteed, this should not be interpreted as a reason to delay starting a family. On the contrary, couples should be encouraged to consider parenthood sooner rather than later and society should work towards social frameworks that is financially and structurally supportive of young families.
Fertility preservation should not compromise the young woman’s future chances of spontaneous conception throughout her natural reproductive lifespan. Therefore, more invasive methods of oocyte cryopreservation such as ovarian biopsy, are only appropriate for oncology patients when there is not enough time to harvest eggs.
Egg freezing is considered a back-up insurance policy. If you never use your frozen eggs because you have achieved your desired number of healthy children, you can donate your eggs, either for research or to help an infertile woman, or you can discard them. Research shows that 63% of women are prepared to donate their unused eggs to research, 11% to an infertile woman and 18% would discard them. 8% would not donate or discard them.
Here at the Fertility & Gynaecology Academy, we are pleased to offer our patients: