Freezing and storing embryos

a) What is embryo freezing and storage?

During in vitro fertilisation (IVF) or intra-cytoplasmic sperm injection (ICSI) treatment, fertility drugs are used to stimulate the ovaries to produce more eggs than usual. These are then fertilised with your partner’s, or a donor’s sperm to create embryos.

Because there is normally a number of unused embryos, some people choose to freeze the good quality unused embryos for use in later treatment cycles or for donation.

b) Is embryo storage for me?

You may consider freezing your unused embryos for the following reasons:

• It gives you the option of using the embryos in future IVF or ICSI cycles, without having to go through the risks, expense and inconvenience of using fertility drugs and undergoing egg collection again.
• If your treatment needs to be cancelled after egg collection (for example, if you have a bad reaction to fertility drugs), you may still be able to store your embryos for future use.
• You want to donate your unused embryos for the treatment of other women or for research.

c) What is your chance of having a baby using frozen embryos?

Due to the freezing and thawing process, your chances of having a baby using a thawed frozen embryo are lower than with a fresh embryo. Your chances of becoming pregnant with a thawed frozen embryo are not affected by the length of time the embryo has been stored for.

d) What are the risks of freezing embryos?

Not all embryos will survive freezing and eventual thawing when they come to be used. Very occasionally no embryos will survive.

It is not uncommon for those embryos that do survive freezing and thawing to lose a cell or two. Ideally the embryos should continue to divide between thawing and transfer.

As embryo transfer is involved in using frozen embryos, the same risks apply.

• In another person’s fertility treatment
If you donate your embryos to another person to be used in treatment, the same rules on donation apply as to donating sperm or eggs.
• If you donate your embryos to research, they could be used in studies, such exploring IVF technology, or in stem cell studies.

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