Fertility Preservation and Cancer Treatments
Fertility preservation is the process by which a person can retain their fertility potential so that a future pregnancy may be possible. For some people, life’s circumstances make it impossible or undesirable to get pregnant right away. This may be because of a medical condition, such as a new diagnosis of cancer or a disease process requiring the use of chemotherapy, and Dallas – Fort Worth Fertility Associates can help.
Fertility preservation refers to egg/embryo freezing for women and sperm cryopreservation for men and typically requires the use of in vitro fertilization. Studies have shown that people of reproductive age preparing to undergo cancer treatment are burdened by the thought of becoming sterile after cancer treatment and although current cancer treatment’s effect on future fertility has been greatly improved, ovarian and testicular damage may still occur.
If a woman undergoing IVF for fertility preservation has a partner, her eggs are fertilized with her partner’s sperm. These fertilized eggs, mow embryos are then frozen or cryopreserved at a very early stage in embryo development (before the fertilized egg even starts to divide) for potential use in the future. Embryos can be safely frozen for years and births have been reported from embryos cryopreserved for more than 15 years.
If a woman does not have a partner, an available option that is still in the investigational stages is oocyte cryopreservation or egg freezing. This process differs from embryo cryopreservation in that the mature eggs obtained during the egg retrieval are not fertilized but rather frozen for future use. Dallas – Fort Worth Fertility Associates does provide this service under an IRB-approved protocol.
One of the main obstacles in freezing eggs is the fact that egg freezing and thawing is technically challenging. This is due to the large size and complexity of the egg. The mature egg is extremely fragile and can be easily damaged by intracellular ice formation during the freezing/ thawing process. It is for this reason that eggs are typically cryopreserved by a process called vitrification.
There are two main methods of freezing embryos and eggs, the slow-freeze method and vitrification.
The slow-freeze method has been around longer and is the standard method used for freezing embryos. Embryos are typically cooled to a temperature of between -30 and -80 degrees over the course of 1.5-2.5 hours and then are placed in liquid nitrogen for long-term storage. The slow-freeze method is less than ideal for oocytes due to the higher water content in these cells.
Vitrification, on the other hand, is the process of cryopreservation whereby the cell is solidified into a glass-like state without the formation of ice.
One of the nice things about oocyte/embryo cryopreservation is that once the eggs or embryos are thawed and used, success rates equal that of the woman’s age at the time of cryopreservation. Meaning that if a 33 year old woman freezes eggs/embryos and doesn’t decide to use them until 5 years later when she is 38, her success rate following an embryo transfer will be that of a 33 year old, not that of a 38 year old when success rates are substantially lower.
Dr. Chantilis Discusses Options for Male and Female Fertility Preservation