What is Cryopreservation?
You may have heard the term “cryopreservation” nd are wondering what it means. Cryopreservation is the process by which sperm, oocytes (eggs), blastocysts, embryos, or whole tissues are frozen to be used at a later time after thawing.
They are preserved by cooling to low sub-zero temperatures. Liquid nitrogen is widely used for cooling, and the preferred temperature for storage of specimens is -196 degree Celsius. At these low temperatures, any biological activity, including the biochemical reactions that would lead to cell death, is effectively stopped.
In order to prevent any damage to the cells during the freezing process, cryoprotective agents such as glycerol, ethylene glycol, sucrose, dimethyl sulfoxide (DMSO), and propylene glycol are used.
Why do we want to freeze sperm, oocytes or embryos?
Cryopreservation provides an indefinite longevity to cells being frozen, which means that they can be used later on in life. There are several reasons why people may decide to freeze specimens:
- Men might choose to freeze their sperm and women their oocytes (eggs) and use them later on in life for IVF cycles (or IUI for men) before undergoing chemotherapy or radiation for cancer treatment, which can lead to infertility.
- Sperm can also be frozen for men who cannot attend on the day of their IVF partners’ egg collection procedure.
- Many couples choose to freeze embryos or oocytes because it provides them the ability to get pregnant later on in life when women are in their 40′s, and it is more difficult for a woman to conceive at this age.
- During an IVF cycle, typically one, two or exceptionally three embryos are transferred into the uterus. After the transfer of fresh embryos, any remaining surviving embryos that are suitable are cryopreserved.
- Occasionally, a uterine abnormality like excess fluid in the endometrial cavity may preclude transfer of fresh embryos, requiring storage of embryos until the uterus is normalized.
- In case of severe ovarian hyper-stimulation, fresh embryo transfer may be cancelled in order to prevent further health hazard. The transfer can take place with frozen-thawed embryos in the subsequent cycle when the ovaries have recovered a normal size.
- Sperm or egg banks are facilities can collect and store specimens from donors.They may be available for couples that cannot produce their own sperm or egg, or are carriers of certain genetic disease.
- Frozen embryos are the property of couples that may elect to donate them to other couples for adoption.
What is the cost of embryo cryopreservation?
Most fertility clinics charge an average of $900/year for freezing and storage of embryos. At the Servy-Massey Fertility Institute, cryopreservation and first year of embryo storage cost $775.