Child born after 20-year embryo storage

A healthy baby has been born from an embryo frozen for almost 20 years — the oldest frozen embryo to result in a live birth. The child's mother, 42, had received ten years of fertility treatment, but couldn't conceive due to problems with egg production.

She was anonymously offered five embryos conceived in 1990 and stored for 19 years and seven months. The donor couple had already given birth after IVF treatment and no longer required the embryos.

The embryos were frozen the day after conception at the single-cell stage. Two of the five embryos survived thawing and were grown in the laboratory for two days before being implanted into the mother's womb. Only one embryo survived the pregnancy, but developed into a healthy baby boy born in May 2010 weighing 6lb 15ozs.

Embryos can be stored indefinitely in theory. But Dr Sergio Oehninger, Director of the Jones Institute for Reproductive Medicine at the Eastern Virginia Medical School who treated the woman told the Sunday Times: 'We do not want to be thinking about having 40-year old embryos in the freezer. We would have a new generation that is using embryos of the older generation'.

The case study published in Fertility and Sterility coincides with new legislation in Britain allowing embryos to be stored for up to 55 years. The previous record for oldest frozen embryo to result in a live birth was 13 years. The birth by a Spanish woman was reported in 2006.

Cryopreservation is a method of slow freezing used to store embryos conceived during fertility treatment for use in multiple treatment cycles.