How Are Embryos Stored in Liquid Nitrogen and What Does the Process Involve from a Clinical and Regulatory Perspective?

Embryo storage in liquid nitrogen is the definitive method for long-term preservation of human embryos created through IVF treatment. The process involves cryopreserving embryos by vitrification at either the cleavage stage, typically day 2 or 3 after fertilisation, or the blastocyst stage, typically day 5 or 6, loading them onto specialist vitrification carriers, and storing them in a validated liquid nitrogen vessel at minus 196 degrees Celsius. At this temperature all biological activity ceases entirely and embryos can be preserved indefinitely without measurable deterioration.

Embryos are loaded onto the vitrification carrier using a system such as the CBS High Security Vitrification Kit, which provides a hermetically sealed closed system that eliminates cross-contamination risk. Each carrier must be unambiguously identified with patient and embryo information in line with HFEA witnessing and traceability requirements. Cryolab supplies Brady cryogenic label printers and Cryomarker pens rated to minus 196 degrees Celsius for reliable specimen identification.

The storage vessel must meet stringent requirements for clinical embryo storage. HFEA-licensed IVF clinics must use validated cryogenic storage dewars such as the CryoNest XL or CryoNest XXL connected to a continuous monitoring and alarm system. Within the vessel, a well-organised inventory system using CBS canisters, Daisy goblets, and Cryocanes ensures every embryo can be located precisely and retrieved safely.

Under current HFEA regulations, embryos may be stored for an initial period of 10 years, extendable up to a maximum of 55 years in defined circumstances. Explore our range of certified embryo vitrification consumables and clinical storage dewars for HFEA-regulated IVF clinics across the UK.