Healthy twins born from 30 year old frozen embryos
Twins have been born from embryos that had been frozen for 30 years, they are believed to be the longest-frozen embryos to result in a live birth.
The twin embryos were frozen in April 1992 and born in October 2022.
The new twins Lydia and Timothy were born to their parents Rachel and Philip Ridgeway on 31st October 2022 – more than 30 years after being frozen as embryos. On March 2, Rachel had undergone a procedure to have three donated embryos placed in her uterus. Two of those embryo transfers were successful and resulted in Lydia, who was born weighing 2.5 kgs, and Timothy, who was born weighing 2.9 kg. The infants’ biological parents, who have stayed anonymous, donated their leftover embryos to the National Embryo Donation Center (a non-profit Christian organisation in Tennessee, USA) after going through in vitro fertilisation in 1992.
Fresh embryo transfer versus frozen embryo transfer
The first live birth following the transfer of thawed cryopreserved embryos was reported in 1984. With refinement of technology over the last few decades, the number of frozen embryo transfers has increased as have pregnancy rates. Evidence suggests that there are no major health differences between babies born from frozen embryos and those born from fresh embryo transfers, according to a review published in 2020 in the journal Reproductive Sciences.
Embryo freezing (cryopreservation) is a method of preserving the viability of embryos by carefully cooling them in liquid nitrogen to a very low temperature of (-196ºC). The low temperature pauses all biological activity in the embryo, and thawing and implanting the embryo allows those processes to resume. The maximum length of time embryos can be cryopreserved in this way and then be able to provide a viable pregnancy and resulting live birth is still unknown.