Embryo freezing

Embryo Freezing involves taking mature eggs (from a young woman’s ovary) and fertilising them with sperm using in-vitro fertilisation (IVF). This is done in a laboratory. The fertilised eggs (called embryos) are then frozen and stored for using in the future. When a young woman is ready to become pregnant the stored embryos are put back into the womb.

Who is it for?

Young women who have gone through puberty and:

• Have time to go through a cycle of fertility treatment before starting cancer treatment
• Have a male partner (because it needs both eggs and sperm to fertilise the egg)

What does it involve?

You will need hormone injections to stimulate the ovaries (ovarian stimulation) for about 2 weeks. Eggs are then collected from the ovaries using a fine needle. This is done under sedation and you may be able to go home a few hours later.

If you are in a relationship and create and store an embryo with your male partner, you will need his consent before the embryos can be used at a later date. This is important, because if you later split up, he may not want you to use the stored embryos.

If you do not have a male partner, donor sperm could be used. If you choose this option, it is important to know that the donor can change their mind, and not allow use of any embryos made using their sperm. Frozen embryos can be stored for 10 years (and sometimes longer in certain situations).

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

There are not many cancer patients who have used frozen eggs so it is difficult to know how likely it is that embryo freezing will result in a successful pregnancy.

Most of the data that shows how successful embryo freezing can be focuses on young women without cancer that have used their frozen embryo to have a baby.

The chance of success with embryo freezing depends on how many eggs are obtained, because these are then fertilised to make embryos before being frozen. If a young woman under 35 has ten eggs obtained and fertilised to form embryos, these will give her a 5 in 10 (50%) chance of having a baby. The chance of having a baby after embryo freezing depends on the following:

Your age when your eggs are collected (young women who are under 35 years old will have a higher chance)

• The number of eggs collected
• The number and quality of embryos frozen
• The health of your partner’s sperm
• The fertility clinic where egg freezing was carried out

You can find more information on the HFEA website (www.hfea.gov.uk) about the number of average success rates and the number of live births for each licensed fertility clinic.

Will this option affect the health of the baby?

No, data suggests that the health of a baby will not be affected.

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

The fertility drugs used to stimulate the ovaries can cause side effects (e.g., headaches, mood changes and hot flushes). These drugs can also stimulate the ovaries too much which could lead to a condition called OHSS. Once you begin treatment ask your fertility care team about the symptoms of this condition and how to get in touch with them if you need to.

When the ovaries are stimulated to produce lots of eggs, the hormone oestrogen increases. This could be a risk for young women who have an oestrogen sensitive breast cancer. These young women can be given a drug called Letrozole which lowers the oestrogen level in the bloodstream.

When the eggs are collected, there is a chance of bleeding, infection and puncture to the bowel but this is rare.

There may be concern for young women with pelvic cancers because cancer cells could spill from the ovary into the abdomen after egg collection.

If more than one embryo is replaced, there is the chance of multiple births (e.g., twins, triplets). All pregnancies have a risk of miscarriage and ectopic pregnancy (a pregnancy outside of the womb).

IVF can be physically and emotionally draining and pregnancy may not happen.

Will this option delay the start of my cancer treatment?

It takes approximately 2 weeks from starting ovarian stimulation to the time of egg collection. This may mean some delay in starting your cancer treatment.

Embryo freezing may not be an option for young women with certain cancers (e.g., leukaemia) because they may need to begin cancer treatment immediately.
If you experience OHSS, this could delay the start of cancer treatment.

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

There is no data to suggest that Embryo freezing affects the chance of cancers growing or returning.