Gamete Cryopreservation

Egg Freezing

Vitrification

The introduction of a new freezing technique known as vitrification has now made egg storage a much more realistic option. In the past eggs have been freeze-stored mainly for 'fertility preservation' ahead of cancer treatment - so the reasons have been 'medical'. However, egg freezing is becoming of increasing interest to a number of women who may not be in a secure relationship and choose to put a few eggs in storage for when, and if, the right man comes along. Putting fertility on hold in this way is egg freezing for social reasons. Vitrification, which is now employed for the storage of eggs and embryos at the London Women's Clinic, is a technique which cools at a very fast rate, such that the tissue is preserved in a glass-like state (hence 'vitrified') without the formation of damaging ice crystals. Vitrification is associated with better survival rates for eggs than previous slow-cooling techniques.

Sperm Freezing

Sperm freezing and storage is the procedure of freezing sperm cells in order to preserve them for future use. Sperm cells have been frozen and thawed successfully for more than 40 years. By using special technologies and then keeping it in liquid nitrogen (-196°C) sperm can be stored for many years while still maintaining a reasonable quality.

Why would I want to freeze sperm?

1. chemotherapy or radiation therapy
2. certain types of pelvic or testicular surgery
3. vasectomy
4. high risk occupations or sports
5. diabetes may cause erectile difficulty
6. male away from home on day of assisted reproductive treatment

Sperm Storage

Sperm can be frozen indefinitely. Scientifically there is no limit to the length of time that sperm can be stored in a frozen state. Damage can occur to the sperm during freezing and thawing, not while it is frozen. The duration of time in storage does not influence the success rate. There is a fee for freezing each semen sample. This fee includes six months storage. After the initial six months, storage costs apply for storing one or more samples at City Fertility Centre. This annual storage fee is regardless of the number of samples stored and is not refundable. Please contact us to ask about our current rates. If you decide to freeze and store your sperm with City Fertility Centre, you must update us about any address changes.

Could there be a problem with the quality of sperm?

Yes, there may be a problem with the number and quality of the sperm, especially in men who are about to undergo cancer treatment. Their underlying illness may have caused a reduction in the sperm count or in the motility (movement) of the sperm. It may be advisable to freeze even more specimens in such situations if time and treatment permits.If the sperm count or motility is low, the thawed samples may not be suitable for Intra-Uterine Inseminations. However, we can still use them for In Vitro Fertilisation (IVF) and Intracytoplasmic Sperm Injection (ICSI), where individual sperm are injected directly into the eggs. These procedures are much more complex and costly, but can result in pregnancies even in cases where the sperm count is very low or the sperm are functionally impaired.

Are there any problems with the children arising from the use of frozen / thawed sperm?

Research has shown no difference in the rates of abnormalities or birth defects among children conceived with fresh versus frozen sperm. However, there are some theoretical concerns that chemotherapy drugs may have unknown effects on the sperm or the offspring. If possible, it is best to freeze the specimens before chemotherapy begins.