Egg freezing involves stimulating the ovaries to produce multiple eggs, removing them during a monitored procedure and storing them at temperatures below -150C for possible use in the future.
An initial appointment with a fertility specialist is likely to include blood tests, a pelvic ultrasound scan and a discussion of the patient’s medical history. If treatment goes ahead, hormone injections are used to encourage the ovaries to produce more eggs than the single egg typically released each month.
The process requires several visits to a fertility clinic over a period of a few weeks. Hormone levels and the ovaries are monitored regularly before the eggs are collected.
When they are ready, a medical professional uses an ultrasound-guided needle and suction device to remove the eggs from the ovarian follicles. Women aged under 38 produce an average of seven to 14 eggs during the procedure.
The eggs are assessed in a laboratory before being flash-frozen by an embryologist using a rapid technique known as vitrification. They are usually stored in liquid nitrogen, where the very low temperature allows them to remain viable for later use.
How long can frozen eggs be stored?
Frozen eggs can be stored in the UK for up to 55 years. The limit, which also applies to sperm and embryos, was extended from 10 years in July 2022.
Patients must renew their consent with the clinic every 10 years. Anyone whose eggs were frozen before July 2022 and wants to keep them for longer than 10 years needs to contact their clinic to establish whether this is possible.
When the eggs are needed, they are thawed and those that remain intact are injected with sperm from a partner or donor. The resulting embryos can then be transferred to the womb.
The cost of egg freezing
The overall cost of freezing and later using eggs in the UK is typically between £7,000 and £8,000, although fees vary between clinics.
Egg collection and freezing cost about £3,350, while the medication used to stimulate egg production adds roughly £500 to £1,500. Storage is charged separately and generally costs between £125 and £350 a year.
Thawing the eggs and transferring them to the womb costs an average of £2,500.
Risks and success rates
The Human Fertilisation and Embryology Authority describes IVF as “mostly very safe”, although fertility medication can cause side effects.
In some cases, women develop ovarian hyperstimulation syndrome, or OHSS. Mild cases can cause abdominal swelling, discomfort and nausea and usually improve with time. More serious cases may require specialist care or hospital admission.
Severe symptoms include extreme thirst and dehydration. In rare cases, the condition can lead to thrombosis, a blood clot in the legs or lungs.
Embryologists regard egg freezing as an insurance policy rather than a guarantee. The likelihood of success depends largely on the woman’s age when the eggs are frozen, as well as the total number collected.
Not every egg will fertilise, not every fertilised egg will develop into a viable embryo, and not every viable embryo will result in a live birth. One US study found that the overall chance of a live birth for women using their own frozen eggs was 39 per cent, rising to 51 per cent among those who were under 38 when their eggs were frozen.
Licensed fertility clinics in the UK are regulated and inspected by the Human Fertilisation and Embryology Authority, which publishes inspection scores for each clinic.
