Expert / 16 December, 2019 / Dr Larisa Corda
Egg freezing has increasingly become a social choice for many women. Women are now more aware of their own biological clock and want to give themselves the best chance to have a child later in life with their own biological eggs. Women are taking matters into their own hands. They’re no longer at the whim of a man’s indecisiveness. Women are feeling empowered at being able to exercise a degree of control over their own fertility, even if life circumstances prove a challenge to starting a family when they may want.
Egg freezing involves the same principles as IVF, your ovaries are stimulated with injections that will make them produce several eggs in one go. When these eggs are mature, they are collected via a short operative procedure that involves using a needle into the vagina and then the ovaries, to aspirate and collect all of the eggs. These eggs are then frozen and preserved for use later on, when they are thawed, fertilized and used to create embryos that can then be used for implantation.
The duration of stimulation varies depending on your response. It’s different for everyone, but on average the process takes between a few days to two weeks. During this time you are monitored with blood tests and scans and encouraged to keep well hydrated, maintaining a healthy lifestyle and avoiding over-vigorous exercise due to the ovaries swelling in size.
Current law in the UK only allows a woman to store her frozen eggs for a maximum of 10 years, unless there is evidence that a woman is at risk of premature menopause, for example, due to cancer. In this case, eggs can be frozen up to the age of 55.
There is a campaign to try and extend the egg freezing limit for all women, in particular as women are likelier to have egg freezing when younger to optimise their chance of success, but at the moment, if a woman freezes eggs in her mid-twenties, her egg storage limit would expire by her mid-thirties, yet not all women will necessarily want to have children by that age.
Egg collection and freezing is expensive and costs between £3000 to £5000 in the UK. Storage costs are extra, around £150 to £400 a year. As all women have different ovarian reserves and are of a different age when undergoing the procedure, some may need more than one round of ovarian stimulation. This is enable the collection of enough eggs to be able to give themselves a decent chance of conception. On average, we estimate that having 15 eggs for storage should allow a good chance but, again, it must be stressed that this number will vary depending on age.
As well as being expensive, the process of egg freezing and IVF can often be emotionally and physically challenging so it’s important to consider confiding in someone you trust to help support you in this process.
Feeling that you’ve done what you could to help preserve your fertility can suddenly take a lot of pressure off. It can be very empowering, giving you a new perspective and a positive attitude to the future. It can often be a great time to start a relationship, where you can focus your attention on whether this person is right for you, rather than how soon you need to start having a family.
However, the success rates for successful pregnancies following egg freezing compared to embryo freezing, are much lower. If you just freeze eggs, you will have no idea about their quality until they are fertilised later down the line when it comes to using them. In essence, you could potentially be giving yourself a false sense of hope. This is why it’s important to offer the option of embryo freezing as well as egg freezing, either with the sperm from your current partner or donor sperm if you are single, in order to maximise the chance of pregnancy later, albeit this option won’t be for everyone.
It’s also important to realise that transferring an embryo later in life is not the same as it is in a younger woman. Pregnancy-related complications such as pre-eclampsia and high blood pressure are more common in older age, so delaying pregnancy for too long can cause problems in itself.
Also, during the time of ovarian stimulation, injections will need to be taken at the same time every day and you will need to attend scan appointments regularly. Make sure you are able to commit to the process and take the necessary time off to be able to do this.
Most miscarriages later in life are due to egg quality being poorer. The reason for this is that all the eggs you will ever have are there from your birth and as time goes on, the genetic material they contain starts to degrade, becoming more unstable and also damaged. This gives rise to a greater likelihood of genetically abnormal embryos. Because of this, success rates vary depending on your age.
As a general rule of thumb, the more eggs that are collected for freezing, the better the chance of success in terms of achieving a pregnancy later in life. However, despite this, success heavily depends on egg quality, which is determined by age. To have a good chance of having one live birth, a 37-year-old woman would need to have close to double the number of eggs frozen that a 34-year-old would, and by the time a woman is over the age of 40, the chance of successful pregnancy with egg freezing becomes very small due to the significant decline in egg number and quality.
It’s important to realise that just because a good number of eggs may be extracted, even over several cycles of stimulation, not all of these eggs will be capable of fertilisation, and not all of the fertilised eggs will be able to produce good quality embryos that can give rise to babies. The birth rate with previously frozen eggs per embryo transfer is around 19%, on average but, again, is heavily influenced by age.
The optimal age to freeze eggs is when you are young, but not too young, otherwise you may never end up using them. Not surprisingly, the highest live birth rates from previously frozen eggs are shown to come from women who undergo the procedure before they are 30. However, the average age at which women freeze their eggs is around 37, with many women closer to 40 by the time they consider doing this. It is generally agreed that the best time to freeze eggs would be under the age of 36 when the eggs are still of sufficiently good quality in the majority of women and you are likely to need to use them in the future. This is typically in your early 30s. Whereas this advice is generally true for most women, the decline in egg number and quality can start much earlier for some, and it’s important to detect this before it’s too late for egg freezing to be an option.
If you’re not sure what clinic to go to when seeking advice about whether egg freezing is right for you or not, the HFEA website has lots of great and useful information to help.
Article by Dr Larisa Corda