Research from the British Fertility Society has suggested that IVF babies born from frozen embryos are heavier and healthier than those fresh embryos.
The study, carried out at the Centre for Reproductive and Genetic Health in London, involved measuring the weight and length of gestation of 384 single-birth babies born after fresh embryo transfer and 108 born after frozen embryo transfer.
Those born from frozen embryos were on average 0.56lb heavier than the fresh babies, though the researchers said they were unclear why this was the case.
Lead researcher Suzanne Cawood said: "The reasons behind these findings are not yet fully understood, but one possibility may be that there is a difference in the uterine environment between fresh cycles, when embryos are transferred soon after the eggs have been collected, compared to frozen cycles when the uterus has not been stimulated in the days before transfer."
It's hoped that more research can be undertaken to confirm this theory, but fertility experts are pleased that the findings do support the recent move to transfering only one embryo at a time.
According to Clare Lewis-Jones from Infertility Network UK:"Single embryo transfer gives the best possible outcome with the chance of further frozen embryo transfers in the future."
Freezing embryos enables prospective parents to have several cycles of IVF from one round of treatment but does increase the possibility of multiple pregnancy.