Cryopreservation in NYC
Cryopreservation refers to the freezing of sperm cells, egg cells, and embryos to be stored for future use. Because of long experience gained in the animal industry involving animal sperm for breeding (mostly cows), it has been possible for decades to freeze human sperm cells, which has been the basis for the establishment of large sperm banks worldwide. The first human pregnancy with thawed frozen sperm was in 1953.
At New York Fertility & IVF Surgery Associates, our fertility doctors use cryopreservation to allow men and women to ‘beat the biological clock’ and increase the likelihood of achieving a healthy pregnancy after their peak reproductive years. If you and your partner are having trouble conceiving, we can help.
Learn more about cryopreservation below, or request an appointment today using the form on this page.
- In an IVF setting, semen is frozen beforehand for patients when the male partner would be unable to be present at the time of egg retrieval to make a fresh semen sample.
- Freezing semen is a fairly simple procedure that involves adding an egg yolk-buffered cryoprotectant solution to the semen to protect the interior of the sperm cells from freezing.
- Ice formation inside a cell will result in irreversible cell damage.
- The mixed semen-cryoprotectant solution is then divided into small portions of 0.5-1.0 milliliter, each placed in tiny plastic vials that can be clamped to a metal holder kept in a cylinder that is plunged into a cryopreservation tank filled with liquid nitrogen at -196o C. The semen can be kept frozen indefinitely.
- Since the late 1980s, IVF laboratories have been routinely freezing embryos that are left over from a patient’s IVF cycle when it results in many more viable embryos than are transferred to her uterus right away.
- These embryos are therefore available for transfer in case she does not get pregnant the first time.
- In a cycle for frozen embryo transfer (FET), the patient does not have to go through stimulation all over. She is simply prepared for the transfer by a two-week regimen of estrogen and progesterone to make her uterine lining ready for the embryo.
The first human pregnancy achieved with a frozen embryo was in 1984. Since then, embryo freezing has become routine in IVF centers. When the technique of vitrification became standardized for egg freezing, it also became the favored method for embryo freezing, because it is much faster than the standard slow cooling protocol that had been in use since the 1980s.
Egg freezing did not become a widespread practice among IVF laboratories until the past 10-15 years because it took a lot oftime to develop a technique that successfully met the technical challenges involved in freezing eggs.
- Although the first successful pregnancy from frozen eggs was recorded in 1986, the success rate with frozen eggs stayed at 1-3% for more than a decade, even in specialized centers around the world.
- The egg cell is the largest human cell, 30 times bigger than a sperm cell., which means that its water content is relatively high.
- Ice formation within the cell – which destroys the cell structure – was an ever-present risk, because ice can form not just during the freezing process but also in the initial stages of thawing.
The problem has since been overcome with advances in egg freezing techniques, which include:
- Appropriate cryoprotectants were formulated that reduce the water content of the egg cell before freezing and therefore minimize ice formation.
- Development of an ultra-rapid freezing method called vitrification in which the cryoprotectant solution containing the egg is rapidly supercooled to a glass-like state which bypasses the formation of ice crystals.