Egg freezing

To maximise the chances of conception following egg freezing, a number of stimulation cycles may be required. From our egg thaw cycles themselves (up to Dec 2018) 1 in every 19 eggs thawed has achieved a pregnancy and 1 in 22 a livebirth/ongoing pregnancy.

Dividing by age, 1 in 15 eggs frozen <35 have achieved a livebirth/ongoing pregnancy, 1 in 23 eggs frozen between 35 to 40 have achieved a livebirth/ongoing pregnancy and 1 in 35 eggs frozen over 40 have achieved a livebirth/ongoing pregnancy.

Clearly, the younger you are, the higher the chance that eggs will achieve success. We would therefore recommend women to freeze at as young an age as possible and aim for at least 20 eggs in storage. However, there is no guarantee of success with any number as other factors such as egg quality are also relevant. Some women may achieve success with only a few eggs and some may be unsuccessful with over 20.

We therefore offer egg freezing packages for those considering more than one stimulation cycle.

The law permits you to store your eggs for any period up to 10 years, so routinely you will get an annual letter confirming that you want to continue to keep them stored.

In cases where you or your partner are prematurely infertile or likely to become prematurely infertile, you may store for longer up to 55 years if a medical practitioner certifies this to be true.

The main benefit of freezing your eggs is that it "locks in" the quality of a woman's eggs at the age they were frozen. These eggs can be used at a later stage when the quality of her own remaining eggs may be significantly reduced in comparison. So, the easy answer would be as early as possible but it is not as simple as that.

Despite the decline in both egg quality and quantity with age, there are pitfalls and risks to both freezing too early as well as too late and it is therefore a difficult balance between any social benefit and the physical, emotional and financial burden of treatment.
In theory the earlier a woman freezes her eggs, the higher the quality and therefore potential future success with them. However, the earlier you freeze them, the less likely you will ever need to thaw and use them in the future as the chances of a natural pregnancy will be higher.

In contrast, waiting until your late 30s or early 40s would allow you more time to start a family naturally. Social trends have shown us that many women may not be ready to start a family at this age or may not have a relationship that they desire at this point and if this is the case, the expected success rate of eggs frozen at this point will be much lower.

Similarly from a social perspective, freezing your eggs may allow you the peace of mind of a potential "fertility insurance policy" for the future if ever needed but there is never any guarantee of success. Freezing should never be seen as a definitive alternative to natural conception as it is not. Such a feeling of false reassurance may be in fact detrimental to overall chances of conception.

So in summary, the longer you wait over time the declining egg quantity and quality will result in a lower chance of having a successful pregnancy.

So we would recommend consideration of egg freezing:

• If embarking on any treatment (such as radiotherapy or chemotherapy) that may impact on ovarian reserve and future fertility
• Ideally in your early to mid 30s if single and not planning to imminently start a family
• In those over 35, depending on social circumstance and your egg reserve, the numbers of eggs needed to give potential success will be higher and the overall chance of future success lower.

Once the eggs are stored, the success rate is "locked-in" at the age they were frozen. The duration they spend cryopreserved has no bearing on the future outcome of treatment.

So, you could freeze them 2 or 10 years before you want to have children with similar outcomes. The key, as we have discussed above, is deciding at what age to freeze them.

No, but this is a common misconception. In any given cycle, a number of follicles with eggs in them will be recruited from your stores ready to respond to your hormones and grow. In a natural cycle, in response to your natural "follicle stimulating hormone" (FSH) they will all begin to grow, before one becomes the dominant follicle that continues to grow from which you ovulate and release the egg within. The rest will in essence wither and die away before a new batch comes through ready for next month if not pregnant.

When we stimulate your ovaries with FSH injections for IVF or egg freezing all we are doing is making this process more efficient by stimulating more of those that have already been recruited. As more follicles grow, this allows us to collect as many eggs as possible. We do not recruit any more than are already there so should have no long-term effect on your fertility or bring menopause on earlier.

Nevertheless, one of the non intended social consequences is the false sense of security that may lead to a further detrimental delay in trying naturally for a baby. Should the frozen eggs prove unsuccessful, they may subsequently be faced with the prospect of trying for a baby with fresh eggs at an older age.