Frozen embryo transfer: the new way to adopt?

Frozen embryo transfers once had an image problem. Loaded into the phrase was the reality that your fresh cycle failed and your chances of success were going down. Not any more. More and more babies are the result of frozen embryo transfers. FET success rates are better than you think.

There are two types of FET. One uses cryopreserved embryos from a previous IVF or donor-egg cycle. The other uses frozen donated embryos, created from donor eggs and sperm. The first is the most common: couples often have leftover embryos from a previous cycle and must decide what to do with them. Embryo adoption, or double donation, is newer. For couples with very low chances of success using their own eggs and sperm, it’s a good option.

Frozen embryo transfers are one of IVF’s best developments. In the early days of embryo freezing, FET success rates were poor. The whole process was imperfect. Embryos were frozen and thawed slowly. Poorer quality cryopreservation agents were added and removed at different stages. It was time-consuming and expensive. This led to poor outcomes.

But then came advanced vitrification. This revolutionised frozen embryo transfers. Success rates started to rise. Super-fast freezing and better preservation chemicals helped reduce ice-crystal formation, which had previously damaged embryos and their component cells.

As IVF techniques continue to improve, and single embryo transfers increase, couples have more leftover embryos. As a general rule of thumb, IVF patients have a 50 per cent chance of having some leftover embryos to freeze. After donor eggs, it’s 80 per cent.

These frozen embryos hold the key to future success. Clinics are selective with the embryos they choose to freeze. With an eye for realistic predictions, blastocyst-only freezing of viable embryos is now commonplace.

There’s good evidence that frozen blastocysts make particularly good candidates for successful cycles. Research suggests frozen embryo transfers are now almost as successful as fresh transfers, and more successful for older IVF patients. FETs are no longer the poor relation to fresh embryo transfers.

FETs are also cost-effective. They’re much cheaper than a fresh cycle and involve a much easier protocol. No FSH medication is used, meaning a more natural stimulation phase (typically estrogen and progesterone support). If you head abroad for your treatment, it’s just a two-day trip.

And that’s why treatment using donated embryos has taken off. The appeal of top-quality, ready-made embryos from healthy donors is clear. PGS-tested embryos maximise success rates even more. Traditional adoption can take years. An embryo adoption cycle can six weeks – and you’re in control. It’s the new way to adopt, and improved FET technology has made this possible.