Egg freezing or “oocyte cryopreservation” is a method used to preserve eggs to be used at a later time. The eggs are protected and frozen in liquid nitrogen. They are placed in a state of suspended animation so that they may be frozen for long periods of time then thawed and used when the patient is ready to become pregnant. The preferred method of freezing is called “vitrification”, which is a special method of freezing that is done very quickly as opposed to the older method of slow freezing. Vitrification, unlike slow cooling which has been used for freezing over the past 20 years, avoids the damage to the cell invoked by ice crystal formation, as well as the “chilling” effects seen with slow cooling. With vitrification, embryos are taken from room temperature to -196º C in a fraction of a second using high concentrations of cryoprotectants.
The patient will undergo IVF with injected medications so that the maximum number of eggs are retrieved. NewLife Fertility Centre will store eggs for as long as the patient desires with an annual renewal of the cryopreservation agreement. The types of patients who may want to access this technology include young women who want to preserve their fertility due to career or lifestyle choices. The choice to freeze their oocytes at a young age will give them the opportunity to conceive at a later time which may be more appropriate for them. The second group of patients who are candidates for egg freezing are those young women recently diagnosed with cancer. Since most cancer treatments involve radiation, chemotherapy, or a combination of both, ovarian function is often compromised causing infertility. If the patient is not in a relationship, the option to freeze just her eggs as opposed to freezing an embryo with partner’s sperm is an option. Once her treatment is completed and she is in a relationship, the frozen eggs can be used with her partner’s sperm.
The option of egg freezing should be discussed with the patient as soon as possible after the cancer diagnosis, so there is time to proceed with the egg collection and freezing prior to any cancer treatments. This many also be an option for those patients who have chronic illnesses whose medication may have a detrimental effect on oocyte function.