Egg cryopreservation (egg freezing) is an advanced fertility preservation technique that allows women to preserve their eggs for future use. This procedure gives patients the possibility to plan a pregnancy at a later time, using their own genetic material.

Egg cryopreservation is useful for medical reasons. For example, if you are going to undergo cancer treatment, freezing your eggs can be an important way of preserving your fertility for the future.

Egg cryopreservation is also possible for social reasons. If you do not wish to become pregnant at present, cryopreserved eggs can allow you to have a child later in life, using your own genetic material and thus preserving your fertility for the future.

Egg cryopreservation is part of the broader fertility preservation process. It offers the chance to use the stored eggs at a later point in time. For more details about preservation treatments, you can also consult the dedicated cryopreservation page (eggs / sperm / embryos / ovarian tissue).

What Is Egg Cryopreservation

Mature eggs (ready to be fertilised) are vitrified so that a woman’s reproductive capacity is preserved, even as time passes. Women are born with all their reproductive cells. Once menstruation begins, these cells start to be used up. The age of the eggs is the same as the woman’s age and determines her reproductive capacity.

Egg cryopreservation means vitrifying the female reproductive cells that would otherwise be lost month by month. It is different from embryo cryopreservation.

Egg cryopreservation is used before assisted human reproduction procedures. It is the process of freezing and storing mature eggs for later use in IVF procedures.

Stages of Egg Cryopreservation

Stage 1: Medical Consultation

The fertility specialist has an initial consultation with the patient. At this consultation you will find out that the egg preservation procedure is similar to… placing money in a bank deposit. You deposit cells (eggs) in a cell bank, which you will use later, when you are socially and emotionally ready.

Stage 2: Hormonal Stimulation

This stage lasts a few days and involves the administration of hormones in order to obtain a higher number of mature eggs than in a natural cycle. It is an essential stage both for egg cryopreservation and for in vitro fertilisation (IVF) procedures.

Stage 3: Egg Retrieval (Follicular Puncture)

This is a quick procedure (5–15 minutes) performed under sedation. In the procedure room, the fertility specialist will retrieve the follicles from the ovaries. The intervention is carried out on an outpatient basis. The fertility specialist then sends the collected biological material to the embryology laboratory.

Stage 4: Cryopreservation (Vitrification)

Immediately after retrieval, the eggs are examined in the laboratory by an embryologist. The collected biological material is washed and prepared for rapid freezing (vitrification). Mature eggs are extracted from the ovaries and vitrified so that the woman’s reproductive capacity is preserved, even as time passes. This egg freezing step is the key moment of the process.

Fertility Preservation through Egg Cryopreservation

Stage 1: Fertility Assessment and Initial Tests

The fertility specialist will perform complete tests that assess your reproductive capacity.

The aim is to estimate the potential number of eggs before the ovarian stimulation cycle. These tests also help the physician determine the necessary dosage of medication:

• Hormonal tests
• Ovarian reserve, which is assessed by transvaginal ultrasound combined with a blood test called AMH (Anti-Müllerian Hormone)
• Screening for infectious diseases – HIV, hepatitis B and C

Stage 2: Controlled Ovarian Stimulation

As in an IVF procedure, you will receive treatment with synthetic hormones. These will stimulate the ovaries to mature all the eggs that have started to develop in that month’s cycle. Normally, the body matures only one egg per month.

In order to retrieve the mature eggs at the right time, the doctor will monitor you with blood tests (to evaluate the ovarian response to treatment) and transvaginal ultrasound. The ultrasound shows the development of the follicles (fluid-filled sacs in which the eggs grow).

Stage 3: Egg Retrieval

After approximately 10–14 days, a minimally invasive retrieval procedure follows, under light sedation. Under ultrasound guidance, a fine needle is passed through the vagina into the ovary. Eggs are aspirated from the follicles and transferred to the laboratory.

Stage 4: Freezing by Vitrification

Ultrarapid vitrification

This is a modern cryopreservation technique that uses cryoprotective agents and ultrarapid freezing. In this way, ice crystals do not form, as they did with older preservation methods. Through ultrarapid vitrification, higher survival rates of the eggs are obtained. Between 90–95% survive after thawing.

The oocyte is the largest cell in the human body and contains a large amount of water. Before it is frozen, it must be dehydrated and the water replaced with a substance similar to “antifreeze”.

The eggs are frozen ultrarapidly and stored in liquid nitrogen at -196°C.

Storage of the eggs

The eggs are stored in a cryobank, where they will be kept safely for an indefinite period.

The egg retrieval procedure is identical to the one used in in vitro fertilisation (IVF). The only difference is that, after collection, the eggs are stored instead of being fertilised.

What Are the Most Common Risks

There are minimal risks associated with the retrieval procedure.

It is possible to lose a proportion of the eggs at the time of thawing. This procedure requires advanced technology and experienced embryology specialists.

However, the risks are extremely low in assisted human reproduction centres with a high level of expertise. Genesis Athens, the Centre of Excellence in Infertility Treatment, is the largest infertility treatment centre in Romania.

When Egg Cryopreservation Is Recommended

Eggs can be preserved for social or medical reasons. This fertility preservation option is important for women who wish to protect their fertility for the future.

Non-medical reasons

• Women who postpone pregnancy for professional or personal reasons. A woman’s chances of conceiving naturally decrease over time, because both the quality and the number of eggs decline. New eggs cannot be created by medical methods or medication.
• Single women who wish to preserve their fertility.
• In cases of low ovarian reserve or a family history of early menopause.

Medical reasons

• Before oncological treatments (chemotherapy, radiotherapy)
• Before surgical interventions that may affect the ovaries
• Genetic mutations that require removal of the ovaries (for example, the BRCA mutation)
• Conditions that impact fertility – autoimmune diseases (such as lupus)

Advantages of Egg Cryopreservation

Egg cryopreservation preserves your chance to have biological children at a more advanced age.

• Pregnancy occurs through IVF with your own eggs (your own genetic material), not with donated eggs.
• There is a high survival rate of eggs after thawing – around 90%.
• You have the possibility to plan pregnancy at the right time for you, while benefiting from future fertility using eggs collected at a younger age.

Genesis Athens, the Centre of Excellence in Infertility Treatment, is the largest infertility treatment centre in Romania. We have a high-performance embryology laboratory and embryologists certified by ESHRE. mai mare centru pentru tratarea infertilității din România. Avem laborator de embriologie performant și embriologi cu certificare ESHRE.

“You deserve to be heard, seen, treated with respect, and supported throughout your life.”

Andreas Vythoulkas

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Chances of Success after Egg Thawing

After thawing the eggs in a controlled process, the pregnancy success rate obtained through IVF is influenced by several individual medical factors, primarily the woman’s age and reproductive health.

How Egg Thawing Takes Place

When you decide that you are ready to have a child, the cryopreserved eggs must be thawed.

Stages of egg thawing and use

• Preparation: Once the woman is emotionally and socially ready to have a child, the frozen eggs are thawed by warming. In parallel, medical treatment is started to synchronise the menstrual cycle with the thawing moment.
• Fertilisation: The thawed eggs are fertilised in the laboratory, either by IVF or by ICSI.
• Embryo monitoring: The resulting embryos are monitored to ensure optimal development.
• Embryo transfer: One or more embryos are transferred into the uterus, in the hope of achieving a pregnancy.

You May Also Use Donor Eggs

If you have not cryopreserved eggs in time and no longer have viable own eggs, you can achieve pregnancy with donor eggs. This process is legal.

In vitro fertilisation with donor eggs is a fertilisation procedure in which eggs from a healthy donor are fertilised in the laboratory and then transferred into the uterus of the woman who wishes to become a mother. More information about egg donation is available on the dedicated egg donation treatment page.

At Genesis Athens, the egg survival rate is over 90%. The pregnancy rate after IVF with frozen eggs exceeds 60%.

Why We Recommend Egg Cryopreservation for Social Reasons

We recommend egg cryopreservation so that you have the chance to obtain a pregnancy using your own genetic material when you are ready.

Because the quality and number of eggs decrease with age, the procedure is considered more effective if it is performed before the age of 35. A younger age at the time of egg retrieval maximises the chances of a successful later pregnancy.

Egg cryopreservation plays an important role in medically assisted reproduction. Women thus gain greater freedom over their fertility. Otherwise, female fertility declines with age.

At 25–28 years, fertility is at its peak. It then begins to decrease. It drops sharply between 37–39 years, and at 41 years of age the chances of having a child with your own genetic material are very low.

Egg cryopreservation therefore allows women to preserve their eggs at a younger age, when their quality is good. You will be able to use them later in life, when you are ready to become a mother.

Why We Recommend Egg Cryopreservation before Cancer Treatments

This procedure is useful before cancer treatments – chemotherapy and radiotherapy.

By preserving eggs before cancer treatments, you can have children safely when you are healthy again.

Why are eggs collected before cancer treatments? Chemotherapy and radiotherapy damage the genetic material (eggs). Eggs are extremely sensitive cells when exposed to oncological treatments.Ovocitele sunt celule extrem de sensibile la tratamentele oncologice.

Egg Cryopreservation – Risks and Limitations

Side effects of egg cryopreservation

Side effects of the process are common but usually not severe and are caused by the natural increase in hormone levels induced by ovarian stimulation during the preparation period. Possible side effects include mood changes, hot flushes, headaches and nausea.

In addition, after the retrieval procedure, you may feel bloated or experience cramps or mild discomfort.

Costs of Egg Cryopreservation

The costs of egg cryopreservation include: costs for ovarian stimulation, egg retrieval, vitrification process and annual storage.

In certain situations, the costs may be partially covered by the National IVF Programme 2025.

Frequently Asked Questions

What is egg cryopreservation and for how long can eggs be stored?
Egg cryopreservation is an advanced fertility preservation technique that allows women to preserve their eggs for future use. They can be stored for as long as you wish.

What is the optimal age for egg retrieval?
The optimal age for a woman is between 23–33 years. The ideal age is around 25 years, when both the number and quality of eggs are at their highest level.

Is the procedure painful or risky?
Egg cryopreservation is not a painful or risky procedure.

How many eggs are recommended for a real chance of pregnancy?
The minimum recommended number of eggs retrieved is 10–15 cryopreserved eggs.

Can egg cryopreservation be performed before oncological treatment?
Yes, cancer treatment is one of the main indications for egg cryopreservation. Egg cryopreservation is performed before chemotherapy, radiotherapy or surgery.

How long does the full procedure take?
The complete egg cryopreservation procedure takes approximately two to three weeks. It involves ovarian stimulation for about 10 days with hormonal injections, followed by egg retrieval under sedation, a procedure that lasts only a few minutes. You can resume normal activities the day after retrieval.

What happens after thawing?
After thawing the cryopreserved eggs, they are fertilised with sperm using assisted reproduction techniques (IVF or ICSI) to form embryos. The embryos are kept in the laboratory for about 5 days. Then one embryo is transferred into the woman’s uterus.

Can cryopreservation be used for egg donation?
Yes, cryopreservation can be used for donor eggs, a method in which donor eggs are frozen for later use in assisted reproduction treatments such as in vitro fertilisation (IVF). This method allows, in accordance with the law, the use of selected, healthy donor eggs.

Why Choose Genesis Athens for Egg Cryopreservation

Genesis Athens, the Centre of Excellence in Infertility Treatment, is the largest infertility treatment centre in Romania.

• We have our own laboratory with state-of-the-art vitrification technology
• Our team of embryologists is ESHRE certified
• We offer comprehensive counselling for every patient
• We have a high success rate in treatments using frozen eggs

By choosing egg cryopreservation at Genesis Athens, you have a safe and effective solution for preserving your fertility for the future, with access to modern technology and an experienced team in assisted human reproduction treatments.

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