Fresh or frozen?

An interesting new piece of research has looked at the effectiveness of freezing all the embryos created during an IVF cycle and then replacing them in a later cycle where no stimulation has been used.  It seems there are concerns that when you stimulate the ovaries, this may have an impact on how well the lining of the womb receives embryos. Not only this, but replacing frozen embryos in a later cycle also reduces the risk of hyperstimulation (OHSS).

The suggestion is that freezing embryos and transferring them later could actually increase pregnancy rates and also make IVF far safer for women by cutting the risk of hyperstimuation - although most women who get OHSS have fairly mild symptoms, it can be extremely dangerous.  Now, researchers from Spain have reviewed all the relevant studies in this area and analysed the results, coming to the conclusion that the chance of a pregnancy is as much as 30% higher if all the embryos are frozen for a later transfer rather than transferring them right away.

As is often the case with these rather interesting news stories, those responsible for the study have said that more research is needed to confirm their findings before making any changes to routine treatments for patients - but it will be reassuring for anyone who is having frozen embryos transferred. We often assume that this reduces the chances of success, but the evidence seems to suggest it could be quite the opposite.