Preserving Fertility

By preserving your fertility, you can control when the time is right to start your family.

Why preserve fertility?

For women, fertility decreases gradually over time and from the age of 35, it begins to drop more rapidly. As the number of eggs available, known as the ovarian reserve, decreases, the eggs also begin to lower in quality. This makes it more difficult for women to conceive naturally as they get older. This is a normal biological process, which cannot be altered.

However, the reality is that today more and more women are choosing to have children later in life. This may be due to personal, social or career circumstances. As a result, many women now preserve their fertility by freezing eggs at a younger age, allowing them to be used in the future.

Through the freezing method known as vitrification, the eggs retain their quality at the time of preservation. This means if you decide you want to have a baby later in life, you can use these eggs and have the same chances of getting pregnant as you would have had at the time of preservation.


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Preservation of Fertility

When is it recommended?

Women who might not be ready for a family right now, but wish to have the option of having children later in life. The best time to preserve fertility is before the age of 35. Beyond the age of 35, it is still possible to freeze eggs however the eggs will likely be lower in quality and quantity, and might not provide optimal chances of a pregnancy if used in a fertility treatment.

Success Rates

Thanks to the freezing technique known as vitrification, we are able to maintain the quality of the eggs until the day they are thawed, with very high survival rates. This rate is currently over 95% for eggs collected from women under the age 35, which is much higher than that of traditional freezing methods. They can also be kept frozen for longer periods, with no time limitation.

When used in assisted reproductive treatment, previously vitrified eggs do not negatively affect the chances of the success in any way, as the oocytes maintain the same quality at the time they were preserved. In addition, the IVF success rates achieved with eggs that have been previously frozen and thawed are equal to those achieved with fresh eggs.


18 – 24 years

Best age to have children from a physical point of view.


25 – 30 years

High chances of getting pregnant without help.


31 – 35 years

Production of quality eggs starts to decline.


36 – 40 years

Low fertility. High risk of chromosomal alterations in the eggs.


41 – 45 years

Very low fertility. The woman’s body prepares for menopause.

What is fertility preservation?

Infografía PreservaInfografía Preserva

Step 1: Your first visit

During your first consultation at IVI London, your fertility specialist will carry out a complete gynaecological examination and run some simple tests in order to assess the status of your fertility. They will then explain the different steps of the fertility preservation process based on this personalised assessment. During your second visit, your treatment pathway will begin.

Estimulación ovárica

Step 2: Ovarian stimulation

Step 3: Egg collection


Step 4: Vitrification of oocytes


Oocyte freezing and embryo freezing, which can often be confused, are in fact two separate processes. The difference? Whether the oocytes are fertilised before or after freezing/thawing. When comparing oocyte freezing with embryo freezing, we know that normally less embryos are generated than the oocytes obtained. Oocytes can be frozen, and can then be fertilised and generate embryos; or they can be fertilised immediately after retrieval and viable embryos can be frozen. In both cases, the survival rates are similar; approximately 90-92% for oocytes and 95% for embryos.

Currently, there is no age limit for egg freezing, although the chance of the oocytes resulting in a live newborn decreases after the age of 40.

La duración del tratamiento oscila entre 13-15 días e incluye las mismas primeras etapas que en un tratamiento de fecundación in vitro hasta la punción.

Egg freezing is normally offered as a procedure on the NHS unless you are undergoing medical treatment that may affect your fertility.

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