Egg Freezing Explained: How It Works, Success by Age, and Cost

Egg freezing, known medically as oocyte cryopreservation, collects your unfertilised eggs, freezes them, and stores them so they can be thawed and used in a future IVF cycle. It is a way to preserve fertility, whether for medical reasons or because you are not ready to try for a baby yet. Here is how the process works, how well it tends to work by age, and what storage and cost involve.

Why people freeze their eggs

Egg freezing is chosen for two broad reasons: medical and elective. Medical (or oncofertility) freezing is offered when a treatment or condition threatens your fertility, most often before chemotherapy or radiotherapy for cancer, or before surgery on the ovaries. Elective freezing, sometimes called social freezing, is done to preserve fertility when there is no medical driver, often because life circumstances mean you are not ready to conceive now. In the UK, NHS funding is more commonly available for medical preservation than for elective freezing, so elective freezing is usually self-funded. Because both the number and quality of eggs decline with age, the reason for freezing matters less than the timing: see age and fertility for why the calendar is the central factor.

How the egg freezing process works

The process mirrors the first half of IVF and takes roughly two to three weeks from the start of injections to collection. You take hormone medication, usually daily injections, for around two weeks to stimulate your ovaries to produce several mature eggs rather than the single egg of a natural cycle. You are monitored throughout with ultrasound scans and blood tests. When the eggs are ready, they are collected in a short procedure under sedation, using a fine needle guided by ultrasound, typically taking about 20 to 30 minutes as a day case. The eggs are then frozen rapidly using a technique called vitrification, which limits ice-crystal damage, and stored in liquid nitrogen. Unlike a full IVF cycle, the eggs are not fertilised at this point; that step waits until you decide to use them. The injections were the part I dreaded most, but bruised stomach aside, the bigger surprise was how administrative it all felt: ordering medication, timing doses to the hour, and learning to mix vials at my kitchen table.

Success rates by age at freezing

Age at the time of freezing is the strongest predictor of whether frozen eggs lead to a baby later, because egg quantity and quality both fall with age, more sharply from the late thirties. Eggs frozen under your mid-thirties are more likely to survive thawing, fertilise, and develop into a viable embryo than eggs frozen in your late thirties or forties. Two figures are worth understanding. First, not every frozen egg becomes a baby: eggs are lost at thawing, at fertilisation, and during embryo development, so several eggs are usually needed per realistic attempt. Second, you should always check what a quoted rate counts, per egg, per thaw, or per cycle, and whether it means pregnancy or live birth, since live birth is lower and the one that matters. Standardised regulator data from the HFEA is more comparable than individual clinic marketing. When you later use the eggs, the chance of success follows the same pattern as any IVF cycle, so it is worth reading IVF success rates alongside this.

Cost and storage

Egg freezing is rarely a single up-front cost; it usually involves several charges across the journey. These typically include the stimulation and egg collection round (including monitoring), the medication, the freezing, and ongoing storage fees charged annually or periodically. Later, if you use the eggs, you pay again for thawing, fertilisation, and embryo transfer, which is effectively the second half of an IVF cycle. Because the figures vary widely between clinics, it pays to ask for an itemised breakdown that separates collection, medication, and storage. Our guide to how much IVF costs explains how these line items add up. On storage duration, the UK law changed in 2022: you can now consent to store eggs for up to 55 years, with consent renewed at least every 10 years. Keep track of your renewal dates and storage fees so eggs are not allowed to lapse.

Is egg freezing right for you?

Egg freezing preserves a chance; it does not guarantee a future baby. It can widen your options, particularly if you freeze earlier rather than later, but success still depends heavily on the age at freezing and any underlying fertility issue. If you are weighing it up, do not delay: fertility is time-sensitive, so speak to your GP or a fertility specialist sooner rather than later, especially before any treatment that could affect your ovaries. A clinic can assess your ovarian reserve and give you a personalised picture rather than a population average.

This guide is general information and support, not a diagnosis or individual medical advice. Please consult your GP or a fertility specialist about your own circumstances.