A Brief Overview of Embryo Storage and Freezing

Today there is an estimated 12 million In Vitro Fertilization (IVF) cycles every year around the world.

While IVF is one of the most common fertility treatment pursued by infertile couples, one of the least-talked about aspects of IVF is that many couples will end up with remaining embryos once their family building is complete.

When families have had as many children through the IVF process as they desire, they embryos remaining in frozen storage at their clinic or in a cryobank. At some point, they must determine what they will do (or not do) with these remaining embryos.

How are embryos frozen? Here is a quick look at some definitions that will help you understand the process:

  • Cryopreservation – the freezing of cells or tissue to preserve it for later use.
  • Vitrification – a commonly used, sped-up process of freezing tissues that involves adding a cryoprotectant to the water before freezing.
  • Cryoprotectant – a type of anti-freeze solution that helps to prevent ice crystals from forming in the water, which can be dangerous to frozen cells and tissue.
  • Freezing process – controlled freezing techniques slowly cool the embryos in the cryoprotectant fluid. The fluid temperature gets as low as -196 degrees Celsius.
  • Straws – Long, plastic vials containing the embryos that are sealed prior to freezing. Usually, there are no more than 1 to 3 embryos in each straw.
  • Dewars – Large, tank-like containers of liquid nitrogen which the straws are placed in.

To date, there has been no significant research showing an “expiration date” for frozen embryos. Recently Nightlight Christian Adoptions Snowflake® program had a baby born from an embryo which had been frozen in 1996… 21 years ago!

For more information about Embryo Donation, Adoption and storage, visit www.EmbryoAdoption.org.