The Lane Fertility Institute has successfully implemented a method of cryopreservation (embryo freezing) known as vitrification, which has resulted in higher success rates for its IVF patients in the San Francisco, North Bay and Novato areas.
Embryo Cryopreservation Q&A
What is Embryo Cryopreservation?
Commonly called embryo freezing, embryo cryopreservation is a fertility tool used in conjunction with IVF to preserve embryos for future implantation. When IVF results in more viable embryos than can be injected, the remaining embryos are frozen and stored for future use. The goal is to store the embryo cryogenically and to maintain its viability for the future. Many IVF children have younger siblings which were technically conceived at exactly the same time. However, they were not implanted until years later due to the increased success of embryo cryopreservation.
What Happens During the Procedure?
Some couples are able to collect a large number of embryo from one egg harvest. Viable eggs that are not inserted in the initial procedure are then frozen in small tubes and kept in storage in the embryo laboratory for future use. The process used by the Lane Fertility Institute to freeze the embryos is called vitrification, which flash freezes the embryo in a matter of seconds. This technique may assist in increasing the chances of implantation in the future.
What kinds of technologies are available for freezing eggs or embryos?
There are now 2 types of freezing technologies that are used in IVF laboratories. The Lane Fertility Institute specializes in the more modern practice of vitrification. The older technology is called slow freezing and the second, newer technology is called vitrification.
Vitrification is like “flash freezing” the embryos. The embryos are submerged into liquid nitrogen at roughly minus 200 degrees. The liquid doesn’t have the time to form crystals and assumes a glass-like state. No damage is caused by ice crystals because they don’t form. Embryo survival after vitrification has significantly improved to 98% from approximately 70% after slow freezing.
When slow freezing is employed to preserve embryos, the freezing is slower and requires the removal of water from the individual cells of the embryo. If water remains, it forms crystals when frozen which act like knives and disrupt the inside of the cells or cut through the outer layer of the cells. A cryoprotectant is added to the cells which replaces most of the water inside the embryo. Under the correct conditions, the cryoprotectant doesn’t form crystals and the embryo can safely withstand cryogenic storage.
How Successful is this Procedure?
The success rates for an embryo surviving the freezing and thawing process are higher using the newer vitrification technology and are closer to the success rates of using fresh embryos for implementation. At the Lane Fertility Institute, the embryology team has extensive experience with the technique of fertilizing previously vitrified eggs. They have achieved egg survival rates of approximately 80%, fertilization rates of over 80%, and pregnancy rates above 50%.