Oocytes are particularly sensitive to cryopreservation processes since they have a number of characteristics that adversely affect their survival. However, improvements to cryopreservation techniques in ova banks through the use of vitrification have made it possible to achieve survival rates that are comparable to those obtained in fresh cycles.
For a number of reasons, pursuing an efficient oocyte cryopreservation programme is now essential to any laboratory.
Doing so can prove to be a means of preserving fertility in patients who are of childbearing age and who have been diagnosed with cancer and whose ovarian activity will be compromised prematurely by the chemotherapy or radiotherapy treatment that they will undergo. The increase in cancer survival rates has means that increasingly more women contemplate maternity once they are well again.
It is also increasingly more common for women to plan for a child at a later stage in their life. However, we must not forget that a loss of fertility in women because of their age can make pregnancy difficult or impossible to achieve. These women can benefit from oocyte cryopreservation when fertility is at its optimum, preserving the option of pregnancy for when they decide that the time has come.
The complexity of maintaining an oocyte donation programme lies fundamentally in the availability of donors. Selection processes are very strict, to the point that only 60% of all candidates are suitable to become donors. The availability of an oocyte storage bank means that we can access oocytes with a wide range of phenotype characteristics whenever necessary.
Last of all, there are situations that can occur during a course of treatment. For example, male partners who are unable to provide a semen sample or when there are no spermatozoa available when the partner’s oocytes are ready in the laboratory. Oocyte vitrification offers the option of additional time to resolve the issue or time to think things through with the patient’s partner.