Cryopreservation of Embryos


Embryo cryopreservation is an established technique whereby embryos, or pre-embryos, are frozen and stored for future use. The primary purpose for cryopreserving pre-embryos is to bank spare embryos that are not transferred during an IVF cycle. Generally, only 1-4 pre-embryos are transferred to the recipient during an IVF cycle. Many times there are more pre-embryos generated during an IVF cycle than are transferred to the recipient. If these pre-embryos are of good quality, patients are encouraged to cryopreserve these for potential future use.


Pre-embryos are routinely cryopreserved at the zygote (fertilized egg), cleaved pre-embryo, or blastocyst stage. The stage at which the pre-embryos are cryopreserved depends on many factors. Such factors as the egg donor's age, the number of zygotes generated, and the quality of the pre-embryos contribute to deciding how many, and at what stage the pre-embryos should be cryopreserved. Before and during an IVF cycle, the physician, in consultation with the Virginia IVF and Andrology Center's embryology staff, will advise the intended parents on cryopreserving pre-embryos.


Freezing all pre-embryos for subsequent transfer may be advised for women who are at a high risk of developing severe ovarian hyperstimulation syndrome following ovarian stimulation for in-vitro fertilization (IVF). Cryopreserving the pre-embryos and delaying pregnancy decreases the risk of ovarian hyperstimulation syndrome. Since pregnancy rates are comparable between frozen embryo transfers (FET) and fresh transfers, our patients have found cryopreservation to be the safe choice.


After pre-embryos are frozen, they must be specially stored and maintained at -196 degrees Celsius in liquid nitrogen tanks to keep them appropriately preserved for future use. Virginia IVF & Andrology Center can maintain storage of your pre-embryos until such time as you choose to utilize them for a future transfer. Currently, there is no evidence that the length of time in storage affects the ability of a cryopreserved pre-embryo to survive and develop into a normal baby.


Cryopreserved embryos are stored in our cryostorage facility under our storage policy.


Deciding What to do with Excess Cryopreserved Pre-Embryos


Virginia IVF and Andrology Center understands the sensitive nature of the existence of pre-embryos created through the in-vitro fertilization (IVF) process. For various reasons, patients may decide that they no longer wish to store their pre-embryos for future use. Under these circumstances the patients have essentially three choices on what to do with their cryopreserved pre-embryos, once they have made the final decision not to personally use them. The following gives a brief explanation of the available choices:


  1. Discard
  2. Many patients feel most comfortable having their pre-embryos discarded. Following receipt of the patient's consent, the IVF laboratory staff will remove the pre-embryos from the cryopreservation tank and discard them through our medical waste disposal process. Medical waste will ultimately be incinerated.


    Virginia IVF and Andrology Center neither encourages nor discourages discarding pre-embryos.


  3. Donate to Research
  4. Some patients would like to have their pre-embryos donated for medical research. Often, patients have a desire to have their pre-embryos donated specifically for stem cell research. For stem cell research, pre-embryos would be thawed and grown to the blastocyst stage (around 6 days), at which time a group of cells that are destined to be the embryo would be removed from the blastocyst and cultured into stem cells. This technique destroys the developing embryo, thus this research does not allow prolonged pre-embryo development. Because of our nationís diversity in religious, moral and ethical beliefs, embryonic stem cell research is a highly sensitive issue. Although currently there is no law that prohibits stem cell research in the United States, the federal government has put restrictions on the use of federal money for embryonic stem cell research. However, several states and private organizations are now supporting embryonic stem cell research.


    In addition to stem cell research, there a variety of potential important research studies for which pre-embryos can be used. It is Virginia IVF and Andrology Centerís policy that no pre-embryo research can be performed without approval for that specific research protocol by an Institutional Review Board (IRB). An IRB is an independent body constituted of medical, scientific, and non-scientific members whose responsibility is to ensure the protection and rights, safety, and well-being of human subjects involved in a research study. Utilizing an IRB for pre-embryo research assures that the research is considered morally and ethically acceptable, and that any patient information is kept protected and anonymous. All Pre-embryos donated for research are stored at Virginia IVF and Andrology Center until such time as its IRB deems a research project acceptable.


    Virginia IVF and Andrology Center neither encourages nor discourages the donation of pre-embryos for research purposes.


  5. Donate for Attempted Pregnancy
  6. Some patients would like to donate their pre-embryos to infertile patients who would like to attempt pregnancy. This donation process can be anonymous or directed.


    1. Anonymous Donation
    2. The Virginia IVF and Andrology Center has an anonymous pre-embryo donation program whereby patients who have donated their pre-embryos are matched to a recipient patient without the identity of either known to each other. If there are suitable numbers of pre-embryos for donation, the donating couple will be asked to provide their genetic information, which is reviewed by a genetic counselor. In addition to extensive blood testing, donating couples will be asked to undergo a medical exam and be asked some specific medical history questions in order to eliminate the risk of disease transmission.


    3. Directed Donation
    4. Patients may wish to donate their pre-embryos to someone they know. This directed donation may be to a family member, a friend, or someone else to whom the donating couple may want to donate their pre-embryos . To donate pre-embryos, the donating couple will be asked to provide their genetic information, which is reviewed by a genetic counselor In addition to extensive blood testing, donating couples will be asked to undergo a medical exam and be asked some specific medical history questions in order to eliminate the risk of disease transmission.


    There are several non-profit embryo donation agencies that assist donors and recipients in directed pre-embryo donation. For some patients, the idea that their offspring may end up living in proximity to them makes donation a difficult decision. If patients have these concerns, they may wish to utilize an embryo donation agency (at no cost to the donor) and donate their pre-embryos to a patient in another area of the country. Under such circumstances, theVirginia IVF and Andrology Center would ship the cryopreserved pre-embryos to a reputable IVF facility in that area, and the pre-embryos would be thawed and transferred to the recipient.


    Virginia IVF and Andrology Center neither encourages nor discourages the donation of pre-embryos to anonymous or directed recipients.


    Deciding what to do with remaining cryopreserved pre-embryos can be very difficult for patients. The Virginia IVF and Andrology Center encourages all patients to explore all possibilities. We welcome you to obtain as much information as possible to make a meaningful and informed decision.


    There is a wealth of information and advice regarding pre-embryo disposition available on the internet. Feel free to give us a call at 804-323-9980 if we can be of further assistance.