Do frozen, rather than fresh embryos lead to better IVF outcomes? That’s the theory being tested by Sydney fertility clinic Genea in a new study announced this week.
Fertility specialists are looking to recruit 200 participants for the study, and will compare success rates between 5-day-old embryos which are frozen, then thawed and implanted in to a woman’s natural menstrual cycle against those that involve the transfer of fresh embryos into a stimulated cycle.
The commencement of the trial comes after an Australian study last month concluded that birth defects were ‘significantly decreased’ amongst IVF babies conceived following a frozen embryo transfer.
"The transfer of a fresh rather than a frozen embryo has been the traditional model for IVF and is promoted by some clinics as the `gold standard'," Genea medical director Associate Professor Mark Bowman said in a statement.
"But the best and quickest way to achieve a healthy baby may be from transferring a single frozen and thawed embryo."
Currently at Genea, success rates from frozen embryos are on a par with fresh embryos. After eggs have been collected and fertilised in vitro, the best-appearing embryo after five days is transferred fresh to the woman during her stimulated cycle. Remaining embryos are frozen in case the first transfer does not result in pregnancy, and transferred during natural mistral cycles.
The success of the second or third-best embryos when transferred in to a natural cycle has led Genea researchers to speculate whether the uterine lining plays a key role in successful pregnancy during IVF. If frozen embryo transfer is indeed found to be superior, it may make the completion of a family more possible for those who use IVF to fall pregnant, as there will have been no wastage of the ‘best’ embryo.
Baby Finnian Hawker, pictured above, was conceived during his mother Sarah’s first frozen embryo transfer with Genea. He is the third child for the couple, who used ISCI to fall pregnant with Finnian’s sister Juliette.
Current rates of pregnancy at Genea stand at 60 percent for all patients, with 90 percent falling pregnant within the first three cycles. It is hoped this new research will lead to successful pregnancies in less cycles.
The best and quickest way to achieve a healthy baby may be from transferring a single frozen and thawed embryo.