Cryopreservation

Cryopreservation is a means of preserving sperm, eggs, and embryos for later use.

DR. GHASSAN HADDAD: Cryopreservation means storing tissue by freezing it—tissue or cells. And when it comes to reproductive endocrinology and our specialty, we’re typically talking about three different kinds of tissues or cells. The first would be freezing off sperm and storing it. The second would be human embryos resulting from in-vitro fertilization cycles. The third would be ovacytes or what we refer to commonly as eggs. Human sperm we’ve been successful in freezing and using to produce successful pregnancies for over 50 years. The first cryopreserved human sperm to produce a successful pregnancy was back in 1953. The same thing for embryos resulting from in-vitro fertilization. The first reported baby born out of frozen embryo transfer was back in 1983. Since then we’ve become extremely successful in cryopreserving human embryos and sperm. The problem has always been cryopreserving the egg. The egg has a cytoplasm, or a body, which has a cytoskeleton, and the cytoskeleton of the egg is extremely susceptible to freezing and thawing. Due to that we have been very unsuccessful until recent years and cryopreservation of human eggs. Here at the Houston Fertility Institute we have had the research protocol and we have been very successful in developing this research protocol for freezing and thawing human ovacytes, or eggs, and we have had excellent success rates with those. This offers an extra option for certain patients who otherwise could not preserve their fertility.