What is egg freezing and how does it work?

Here’s what you need to know if you’re considering putting your eggs on ice.

Lauren Taylor
Tuesday 20 June 2023 11:07 BST

New figures show a dramatic rise in the number of women deciding to freeze their eggs.

A report from the Human Fertilisation and Embryology Authority (HEFA) found that egg and embryo freezing are now the fastest growing fertility treatments in the UK.

Egg freezing and storage saw a 64% rise between 2019 and 2021 – increasing from 2,576 cycles to 4,215 completed.

What is egg freezing?

It’s where a woman’s eggs are extracted and frozen immediately for fertilisation at a later date.

Gynaecologist Dr Larisa Corda said it’s a “means of helping preserve fertility for the future”.

Freezing the eggs at the point of extraction means they avoid the decline in quality that’s associated with ageing.

“It essentially means that a woman becomes her own egg donor later in life, when she decides she wishes to have children,” she said.

What’s the process?

“It involves the same sort of procedure as the first part of IVF, where a woman takes injections to stimulate her ovaries, to encourage follicles to grow and lead to egg maturation over several days.

“After that, the eggs are collected via a simple surgical technique using a needle placed into the vagina and then into the ovaries, to aspirate the eggs which are there,” Corda said.

The daily injections (usually for eight to 11 days) involved in the first part of the process is to encourage the ovaries to produce more eggs. “They may be uncomfortable and lead to side-effects like bloating, abdominal pain, nausea, headaches and other hormonal symptoms, such as breast soreness and changes to your mood,” she added.

Women are usually put to sleep for the egg retrieval, during which, a long needle is inserted into the vagina to reach the ovaries and remove the fluid in each follicle that contains an egg.

“This is all done under direct ultrasound guidance and normally takes around 30 minutes. You will not feel anything during the procedure, but afterwards, you may have some cramps and a bit of bleeding, which all normally settles down within 24-48 hours.”

How many eggs are usually frozen each time?

It really depends how many are produced by the patient at the time. Corda said the number of eggs doesn’t give a good indication on the quality though – which is only revealed after the eggs are fertilised to create embryos further down the line, when the woman or couple want to try to have a baby.

“Because of this reason, women are advised to freeze between 10-15 eggs, to give themselves a good, reasonable chance. This may involve doing several rounds of egg freezing, but there’s no guarantee of success,” she said.

The aim varies depending on the clinic though, and the “numbers needed when older become much more unpredictable, and it also becomes much harder to get a good number of eggs too”.

What’s the success rate?

The success rates are dependant on age and the quality of the eggs.

“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,” she noted.

“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.”

She said it’s generally agreed that the best time is before age 36, when most women’s eggs are still a sufficient quality and you’re more likely to use them in the future (as opposed to someone age 25 and more likely to fall pregnant without medical assistance).

It’s important to know that some eggs won’t actually make it, even if they were fine at the freezing stage.

Dr Suvir Venkataraman, from the Harley Street Fertility Clinic, added: “For a good prognosis patient, i.e. under 35 with no known fertility issues, roughly 90% of eggs survive freezing and thawing by vitrification.

“Approximately 70% of those will be fertilised by good sperm to create embryos. Approximately 50% of those embryos will develop well. And there’s approximately 30% chance of live birth per embryo transferred.”

How much does it cost?

The Human Fertilisation and Embryology Authority (HFEA) estimate the average cost of freezing eggs is £7,000-£8,000 – including medication, storage costs and the later process of thawing and transferring to the womb. But it varies from clinic to clinic.

What else should you consider?

Arm yourself with all the facts on the costs, and understand it’s not a guaranteed insurance policy for getting pregnant in the future.

“It’s important to see a fertility specialist to get assessed before considering egg freezing, as the decline in egg number and quality can start much earlier for some women,” Corda said. “If you’re not sure what clinic to go to, the HFEA website has lots of great and useful information to help you to decide and check out their credentials.

“Egg freezing does not offer any guarantees, but for a lot of women, it is the best possible chance of having their own biological children later in life.”

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