Very interesting information on Human Embryo Cryopreservation.
http://www.ivf.com/cryoperm.html
BACKGROUND
In the course of an IVF treatment cycle, more viable embryos may be produced than are desired for embryo transfer in that same cycle. If so, these "excess" embryos can be preserved by freezing and stored for future use. In addition, there are conditions under which the physician managing your treatment will recommend that all embryos be frozen and that no embryo replacement be performed during your IVF treatment cycle. One such reason for this recommendation would be if the patient were at high risk for hyperstimulation syndrome at the time of your oocyte retrieval. Hyperstimulation syndrome is exacerbated by pregnancy and is easier to manage if the patient is not pregnant. In this situation, all viable embryos will be frozen and the replacement of thawed embryos will be performed only after the patient has recovered from the hyperstimulation.
Embryos may be frozen immediately after fertilization at the pronuclear stage, during early cleavage (2 to 8 cell stage) and after 5 to 7 days of culture at the blastocyst stage. If the patient and spouse consent to cryopreservation, the stage at which any embryos are frozen will be determined by laboratory personnel in conjunction with the physician managing your treatment.
The embryos will be stored in the frozen condition until the patient and spouse request their use and the physician responsible for your care determines that appropriate conditions exist in the patient for transfer of the embryos into the patient's uterus. At that time, some or all of the embryos will be thawed. Each embryo will be examined to determine whether it is potentially viable, and if so, the transfer into the patient's uterus will occur.
The pregnancy success rate with frozen embryos transferred into the human uterus is approximately the same as with non-frozen embryos.
However, some embryos do not survive the freezing process. Potential benefits of embryo freezing are an increased opportunity of achieving a pregnancy without undergoing multiple egg retrievals, a reduced risk of a multiple pregnancy (twins or more) by reducing the number of embryos transferred during the IVF treatment cycle, and better management of complications associated with the IVF treatment cycle such as hyperstimulation as described above.
RISKS AND LIMITATIONS
* Establishing an IVF pregnancy using frozen thawed embryos cannot be guaranteed for any woman.
* Some or all embryos may not survive freezing and thawing.
* Additional expenses are associated with the use of embryo freezing.
* Embryo freezing has been successfully used in animals with no known adverse results. There is, however, relatively limited experience with human embryos. Although no increased rate of birth defects have been reported from the relatively limited number of births from frozen human embryos, the risks associated with human embryo freezing, thawing and transfer are not well established at present.
* Failure of storage containers can result in the loss of liquid nitrogen and damage or kill all of the embryos. Embryos are stored in industry standard cryo storage tanks, that are monitored regularly for liquid nitrogen level and maintained at greater than 75% of their capacity. Also the tanks are monitored by an alarm system that will signal laboratory personnel should liquid nitrogen levels become dangerously low. Even so, there is the potential that a tank might fail due to a spontaneous loss of vacuum or rupture of the vessel. Also disasters such as fires and storms as well criminal acts could damage the building housing the tanks and/or the tanks themselves. Any such event could result in the loss of the specimens.
* You must agree to and accept future disposal of any remaining unused frozen embryos. You must determine prior to your IVF cycle whether you will in the future consider donating your remaining frozen embryos to a known couple or to GRS to offer to another couple for anonymous adoption or if you think there may be a need for a gestational carrier in the future in order to begin testing required by the FDA. I/We have been counseled by my/our physician on the FDA regulations and have had the opportunity to have all questions answered.
So my question to SF is this, KNOWING that some embryos do not survive the freezing process, should we then consider making IVF using frozen embryos against the law to keep the prospective parents and the medical staff from committing homicide?