Published online by Cambridge University Press: 02 March 2009
Embryo cryopreservation is a well established technique and is used widely for embryo banking of genetically valuable strains of mice, the transport and proliferation of farm animals and as a valuable adjunct to human in vitro fertilization (IVF). The range of methods presently used to cryopreserve human embryos has been recently reviewed. This article examines the results obtained by the established freezing techniques and developments in the new rapid cooling methods. There is a dramatic contrast in the simplicity, ease and cost between these new rapid techniques and the conventional slow cooling or equilibrium freezing methods and it is likely that the rapid freezing will replace conventional freezing by slow cooling which is presently in widespread use in IVF clinics.