In Vitro Fertility Goddess.
Monday 10 November 2008
Source: Oxford University and Colorado Centre for Reproductive Medicine
Fertility-challenged couples could double their chances of a successful IVF pregnancy and cut the rate of multiple births thanks to a new embryo quality screening technique developed by British and American scientists.
Previous techniques only allowed for about half of all of the embryo's chromosomes to be counted.
But this new method, called comparative genomic hybridisation or CGH, allows for all the chromosomes to be tested.
And given that defects in chromosomes are thought to be the biggest cause of miscarriage particularly in older women, getting the right embryo implant is vital.
The first trial of the procedure achieved outstanding results.
Of 23 women to have their embryos genetically screened with the new technology, two have given birth while another 16 are currently pregnant and have passed the point at which miscarriages typically occur, while another two became pregnant but miscarried.
The 78% success rate is that much more remarkable given all the women were not only aged between 37 and 42, they all had a history of failed IVF attempts and/or miscarriages.
Lead researcher Dagan Wells from the University of Oxford has applied for permission from HFEA to offer the test at the Oxford Fertility Unit at a cost of about £2,000 per screening.
Dr Wells said after the release of his study that "the pregnancy rates we've got so far are absolutely phenomenal. The probability that one embryo leads to a pregnancy is doubled which means that you've got a much better chance of a pregnancy if you do a single embryo transfer."
The new procedure, developed with researchers from the Colorado Centre for Reproductive Medicine, also removes some of the risks associated with existing pre-implantation screening as it involves testing IVF embryos when they reach the blastocyst stage of 100 to 150 cells, allowing for extra cells to be removed for genetic analysis, therefore increasing the accuracy of such a test.
Mandy Katz-Jaffe, of the Colorado centre, said: "This is still a trial, and we don't offer it yet as a clinical procedure. But this is very promising."
Sarah Willams
