Embryo Cryopreservation

Overview

Embryo freezing (cryopreservation) freezes and stores fertilized eggs for later use.  The ability to preserve embryos can help people get pregnant at a future date.

Why would you freeze an embryo?

• Postpone implementation to a later date.
• A backup option in case attempts at fertility treatments fail.
• Preserve fertilized eggs before starting chemotherapy or radiation therapy.
• Ability to donate unused embryos to other people trying to get pregnant or for research.

Is IVF more successful with frozen embryos?

Scientists do not yet agree on whether pregnancy has better changes with fresh or frozen embryos. Success rates are comparable to fresh embryos.  Research in this area continues.

Embryo Storage Methods

Slow programmable freezing (SPF)

SPF lowers the temperature of the embryo to -321F over a few hours' time.  

Vitrification 

Vitrification "flash freezes" the embryo extremely quickly ~ 1 second and was only recently technically possible (mid 2000s). 

Both methods use a cryoprotective agent (CPA) that acts something like an antifreeze and prevents ice crystals from forming in the cells during freezing.