Egg Freezing (Oocyte Cryopreservation): A Guide to Preserving Your Fertility

In short: Egg freezing stores a woman’s eggs for later use, for medical reasons such as chemotherapy or severe endometriosis, or for social reasons such as late marriage. Results are better before the age of 35, eggs can be stored for up to 10 years, and freezing does not increase chromosome abnormalities. It does not guarantee pregnancy, but it gives a real chance of having a child later.

Oocyte cryopreservation, more commonly known as egg freezing, is a procedure that allows a woman to preserve her eggs for use later in life. This option gives women greater flexibility to plan motherhood around medical needs or personal circumstances, and it has become an important part of modern assisted reproductive technology. By preserving eggs at a younger, healthier stage, women may gain more reproductive choices and a better chance at a healthy pregnancy in the future.

• Who may benefit from egg freezing?

• Patients about to undergo treatments that can affect fertility, such as chemotherapy or radiotherapy
• Women who wish to protect their fertility against age-related decline
• Those at risk of early loss of ovarian function
• Women who haven’t yet found the right partner but want to preserve future fertility options
• Patients undergoing IVF who prefer not to freeze embryos for religious or personal reasons
• Women carrying a breast cancer gene mutation who are planning preventive ovary removal
• Patients with severe endometriosis who want to safeguard their fertility
• Situations where sperm cannot be obtained on the day of egg retrieval during an IVF cycle

How is egg freezing performed?

• Hormonal injections are used to stimulate the ovaries so multiple eggs can develop.
• Once the eggs reach maturity, a trigger injection is given to complete their final maturation.
• The eggs are then retrieved in a short procedure (transvaginal or, less commonly, transabdominal) performed under sedation, so discomfort is minimized.
• The eggs are frozen within a few hours of retrieval, after the embryologist has checked which ones are mature, using ultra-rapid freezing (vitrification).

Because eggs contain a large amount of water, freezing them directly could cause ice crystals to form and damage the cell. To prevent this, the eggs are carefully dehydrated using a specialized technique before freezing, which helps protect their structure and quality.

What are the risks of the procedure?

• Ovarian hyperstimulation syndrome (a reaction to fertility medication)
• Bleeding or infection related to the egg retrieval procedure
• Ovarian torsion, caused by temporarily enlarged ovaries
• A false sense of security that may lead some women to delay family planning longer than advisable

Your fertility specialist will discuss these risks with you in detail and monitor you closely throughout the process to reduce them as much as possible.

How long can eggs stay frozen?

Eggs frozen by vitrification do not lose quality with time in storage, so the storage period is set by local law rather than by biology — in some countries it is 10 years, while others allow much longer (for example, up to 55 years in the UK since 2022).

Does egg freezing increase the risk of chromosomal abnormalities?

Current evidence suggests that egg freezing itself does not increase the risk of chromosomal abnormalities in the resulting eggs or embryos.

How is egg quality assessed before freezing?

• Checking under the microscope that each egg is mature (metaphase II) — mature eggs are the ones frozen; some laboratories also image the spindle structure inside the egg

• Measuring the size of the spindle
• Specialised tests such as spindle imaging or polar body biopsy are used only in selected research or genetic-testing settings; they are not part of routine egg freezing, and no test can yet reliably predict which frozen egg will result in a baby

What happens when you’re ready to use your frozen eggs?

When you decide to move forward, the eggs are carefully thawed and fertilized using ICSI (intracytoplasmic sperm injection).

Why is ICSI needed with frozen eggs?

The freezing process causes the outer shell of the egg to become firmer, making it harder for sperm to penetrate naturally. ICSI overcomes this by directly injecting a single sperm into the egg, helping support fertilization.

• Outcomes with frozen eggs depend largely on a woman’s ovarian reserve and age at the time of freezing, with better outcomes generally seen in women under 38.

The number of eggs stored matters as much as age: for women who freeze before 35, around 10–15 mature eggs give a good chance (roughly 70–85%) of at least one baby, whereas after 38–40 more eggs are needed and the chance per egg is much lower. For this reason, egg freezing for age-related reasons works best when done before about 35–36 years. Research has shown fertilization and pregnancy rates to be broadly comparable between fresh and frozen eggs, though individual results can vary.

In conclusion, egg freezing is not a guarantee of future pregnancy, but it can offer women valuable flexibility and hope for having biological children later in life. If you’re considering egg freezing or would like to learn more about whether it’s a suitable option for your situation, the team at Dr. Najeeb Layyous’s clinic is here to guide you through your fertility journey with personalized, compassionate care.

Dr Najeeb Layyous F.R.C.O.G

Consultant Obstetrician, Gynecologist and Infertility Specialist