It is twenty five years ago this March (2009) that the first child from a frozen embryo came into the world. Zoe Leyland was born at the Queen Victoria Medical Centre in Melbourne, Australia on 28 March 1984, helped on her way by Dr Alan Trounson and Dr Carl Wood who made medical history. The decision to try 'test tube' fertilization and embryo freezing was taken by them and Zoe's parents – mother a 33 year old New Zealander and father a 38 year old British born Australian resident. Her mother had hormonal stimulation and produced eleven eggs which were frozen using a new type of controlled rate freezer made by London company Planer plc. One of these frozen embryos became Zoe who weighed in at about 5 lbs or 2.5 kilos.
Zoe and Professor Trounson set a trend and since then, of the three million or so babies born via assisted reproduction IVF techniques, some 20% or about 600,000 are estimated to have been created from frozen embryos. The world's first 'fresh’ test tube baby was Louise Brown born in England in 1978, but Zoe came from an embryo that had been frozen for a time before being thawed and implanted. To allow cells to survive liquid nitrogen temperatures (-196°C) the embryos had to be treated with cryo-protectant, then frozen down in the Planer freezer with extreme precision using different temperature ramps before they could be stored in liquid nitrogen. This controlled rate freezing procedure was a breakthrough in 1984 but is now common and most IVF laboratories worldwide have rate freezers. Freezing an embryo allows physicians to mitigate multiple births by replacing one embryo at a time and storing others or spares for later use; it may also help in allowing a patient to 'recover hormonal equilibrium' by delaying implantation until the drugs to induce the production of multiple eggs have cleared her body. Rate frozen embryos appear to develop into equally healthy children compared with ‘fresh’ IVF ones. Recent studies from Denmark, Australia, the USA and Finland have indicated they are even healthier.
The controlled rate freezing technique, originally suggested over thirty years ago by British Scientist Professor David Pegg, enabled Planer plc to pioneer this equipment. Many thousands of units are in constant use all over the world in IVF labs, hospitals and research institutions. Controlled rate freezing is needed before storing many cells in liquid nitrogen – in areas such as cord blood banking, bone marrow transplants, botanical matter, semen, oocytes, botanical seeds, skin, ovarian tissue, heart valves and blood vessels.
Professor Alan Trounson, currently president of the California Institute of Regenerative Medicine, became a world authority on assisted reproduction and went on to pioneer work in the stem cell field. Alan Trounson is now based in San Francisco and has had a highly distinguished career in assisted reproduction, stem cell and gynaecological research in academic institutions after Monash University in Melbourne.
Recently Louise Brown, the first IVF baby, had her own child naturally – Zoe has no such plans yet and having finished her degree is working in Melbourne.