New IVF record
A baby was born in the USA from a 27-year-old frozen embryo
Polina Loseva, N+1
In the United States, a girl was born from a fertilized embryo, which was frozen for a record 27 years, CNN reports. The previous record – 24 years – was set by her sister, who was born in the same family a few years ago. Both girls, according to doctors, are healthy – which means, theoretically, human embryos can be kept frozen for longer.
During in vitro fertilization (IVF), more embryos are often formed than necessary. This is due to the fact that after hormonal stimulation, embryologists try to take the maximum number of eggs from the mother – as a safety net, in case there are problems with fertilization or the embryos turn out to be unviable. As a rule, during IVF, one embryo is transferred to the uterus, and they try to leave a few more in reserve – if the first one does not take root.
But it also happens that a woman quickly manages to get pregnant, and extra embryos remain. In such a situation, parents have several options. They may ask the clinic to destroy the embryos, take them for scientific research or freeze them for the future – for example, to return in a few years and not undergo a full IVF cycle, but to plant an already "ready" embryo. In addition, in some countries, embryos can be left in the clinic as donors – so that some infertile couple can later adopt them.
No one knows how long such embryos can wait for their new parents and whether they will deteriorate in the process. It is believed that modern freezing technology (vitrification) allows you to store germ cells and embryos indefinitely. Human spermatozoa remain functional for at least 40 years of storage, sheep spermatozoa – 50, and the maximum "shelf life" is still unknown. And it is quite difficult to calculate it with regard to embryos, since they were frozen in different countries almost 40 years ago, and of course there is no unified register of them.
Until recently, the record holder was a boy who was born 20 years after fertilization of the embryo. But in 2017, a girl was born from an embryo that had been in liquid nitrogen for 24 years. Her parents told CNN in an interview that they were not going to set world records, but simply chose a donor embryo based on the growth of its biological parents (since it is easier to give birth to a small child) and their medical history. Later they found out that they got a very "old" embryo, but this period, according to doctors, did not affect the health of the newborn.
In 2020, the same couple decided to adopt another embryo – the sister of the first girl. The second daughter was born at the end of October. As a result, although embryologists created them at the same time, the second girl is now three years younger than the first. But she has a longer life span in freezing – 27 years – and this, apparently, is a new world record. At the same time, both girls, if we count from the moment of conception, are not much younger than their mother, who is now about 29 years old.
Thus, the maximum shelf life of human embryos has once again increased. Whether it has a theoretical limit is unknown. However, additional years of storage increase the risk of an embryo getting into an "accident" – like the one that occurred in May 2020 in one of the American clinics, when about four thousand frozen embryos and eggs died due to an increase in temperature in the storage.
Earlier we already told that special epigenetic marks were found on the DNA of children born after IVF – which, however, did not affect their health. In addition, recently doctors managed to use an immature egg for the birth of a child: it was taken from the mother before chemotherapy, grown in the laboratory, frozen and planted back after the woman had coped with the disease.
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