Freezing - introduction


There are three freezing options which may help preserve a woman’s fertility:

Eggs, embryos and ovarian tissues can be frozen and stored for many years. When the time is right, they can then be thawed and used for a pregnancy after cancer treatment has been completed.

Different methods of freezing are available to preserve eggs, embryos and ovarian tissue. Cryopreservation is a method of ‘slow freezing’. Vitrification is a newer method of ‘fast or flash freezing’. This method has been shown to improve the chance of eggs and embryos surviving the thawing process and make the pregnancy success rate higher.

Some women, if they have a male partner, may be able to freeze both eggs and embryos. They may have more fertility options available to them in the future after their cancer treatment.

Ovarian tissue freezing is a new method of fertility preservation. This could be another option for women with no male partner.

Egg freezing

This option is when matured eggs are removed from the ovaries and frozen. This process is sometimes called ‘egg banking’. When the woman is ready to become pregnant, the stored eggs are fertilised with sperm and put back into the womb.

Who is it for?

Women who want to preserve their fertility and who have gone through puberty, and who either:

  • Do not have a partner.
  • Do not want to use donor sperm.
  • Do not want to choose embryo freezing because of their beliefs.
  • Have time to go through a cycle of fertility treatment before starting cancer treatment.

For some women who have cancer in the pelvis, it may not be safe to carry out egg freezing because of the chance of spreading the cancer.

What does it involve?

You will need to have hormone injections to stimulate the ovaries (ovarian stimulation) for about 2 weeks. Eggs are then collected through a fine needle passed through the wall of your vagina up to the ovaries. This is done under sedation. You may be able to go home a few hours later.

As egg freezing only involves the woman, there is no need for partner consent to use the stored eggs in the future. Frozen eggs can be stored for 10 years. This can be raised by 10 year periods (up to 55 years in total) in some situations.

What is the chance of having a baby after egg freezing?

It is difficult to be certain how likely it is that egg freezing will result in a live birth. The number of cancer patients who have used frozen eggs is small. Most of the data comes from women without cancer who have used their own frozen eggs or donor frozen eggs to have a baby. Eggs that have been slow frozen or vitrified have also been included in this data.

This data shows the chance that egg freezing will help a woman to have a baby is 40% for women cryopreserving 10 eggs at age under 35, and lower for older women.

The chance of having a baby after egg freezing depends on a number of factors. These are:

  • Your age at the time the eggs are collected. Women who are younger than 35 years of age have a higher chance. Women over 35 years old will have a lower chance.
  • The number of eggs collected. Women who have more eggs collected have a higher chance.
  • The fertility clinic where egg freezing has been carried out.
  • The use of slow freezing or vitrification to freeze and store the eggs. Vitrification has a higher success rate.

For more information on national average success rates and the number of successful live births for each licensed fertility clinic visit the Human Fertilisation and Embryology Authority (HFEA) website

Will this option affect the health of the baby?

No, the data suggests that the health of a baby born using frozen eggs will not be affected.

Are there any side effects of the fertility treatment used in egg freezing?

The fertility drugs used to stimulate the ovaries can cause side effects, such as headaches, mood changes, hot flushes, and irritation of the skin. The fertility drugs may also cause the ovaries to over respond and this may lead to a condition called Ovarian Hyper-Stimulation Syndrome (OHSS). Once you start your treatment ask your fertility care team about the symptoms of this condition and how to contact them if you need to.

When the ovaries are stimulated to produce lots of eggs, the levels of the hormone oestrogen go up. This could be a risk in women who have an oestrogen sensitive breast cancer. These women can be given a drug called Letrozole (Femara). This lowers the levels of oestrogen in the blood stream.

At the time of egg collection there is a chance of bleeding, infection and puncture to the bowel, but this is rare. There may be a risk for women with pelvic cancers, where there could be a spill of cancer cells from the ovary into the abdomen following egg collection.

Will this option delay the start of my cancer treatment?

It takes around two weeks from the time of starting ovarian stimulation until the time of egg collection. The time before the start of stimulation can be different depending where a woman is in her menstrual cycle. Egg freezing may not be an option for women with cancers such as leukaemia, some lymphomas, and sarcomas as they may need immediate treatment. If you experience OHSS, this may cause a longer delay to the start of cancer treatment.

Will this option affect my chances of the cancer coming back?

There is no data to suggest that egg freezing affects the chances of cancers growing or coming back.

You may find it useful to write down what you like about this option and what worries you about this option.

These notes may help you talk about whether or not this option is best for you with your cancer care team and fertility care team, partner, family and friends.