Research suggests frozen embryos more likely to boost IVF success

IVF pregnancies that use frozen embryos are more likely to lead to complication-free, full-term pregnancies resulting in healthy babies, research has found. Pregnancies where an embryo has been frozen and then thawed, as opposed to being implanted directly after fertilisation, are also less likely to lead to bleeding during pregnancy.

Scientists have proposed numerous reasons for this, mainly linked to the fact that there is a longer gap between fertilisation and implantation.

With IVF treatment, the ovaries are stimulated to produce a large quantity of eggs which are then removed, fertilised and re-implanted three to six days later, with the rest of them being frozen for future use.

It is possible, researchers have said, that the lining of the womb may not have recovered fully from the procedure to recover the eggs, leading to increased chances of problems.

Standard practice is for the best quality embryos to be implanted straight away, with other “good enough” embryos frozen and stored for future use.

This has led to scientists’ other suggestion that pregnancies are more successful because only the strongest and “best quality” embryos survive the freezing process.

Scientists have analysed over 37,000 pregnancies to come to this conclusion, which some say could lead to the inclusion of egg-freezing as a standard NHS practice. At the moment it is considered an extra service that patients must pay a supplement for.

Senior lecturer at the University of Aberdeen, Dr Abha Maheshwari, said: “Our results question whether one should consider freezing all embryos and transfer them at a later date rather than transferring fresh embryos. In the meantime, my advice to women undergoing IVF is that there is no reason, yet, to change the way they approach IVF.”

Abbie Cavendish