Embryo cryopreservation / freezing is a well-established form of assisted conception treatment.
Sometimes following Embryo Transfer there may be surplus embryos that are of good quality. These can then be frozen and used (thawed) at a later date during a FET cycle (Frozen Embryo Transfer).
The first frozen embryo baby was born in 1984. Embryo cryopreservation allows multiple embryo transfers from a single egg collection and improves the chances of a live birth from a single surgical intervention.
Not all embryos are suitable for freezing as they must be of adequate quality to endure the freezing and thawing process. Approximately 50% of women undergoing IVF / ICSI at the Merrion Fertility Clinic will have additional good quality embryos available for freezing.
Embryo freezing techniques have improved dramatically over the years and especially since the development of ‘Vitrification’ which has now replaced the old method of ‘slow-freezing’. Vitrification is a rapid freezing technique which aims to minimize the amount of cell damage that occurs by ice formation. Instead embryos are frozen in a ‘glass-like’ state. Merrion Fertility Clinic were the first clinic in Ireland to be licensed to perform this technique and survival rates of embryos have improved from ~70% to >90%.