London - A new test developed by British scientists could more than double the success rate of IVF treatment to 80 percent, it is claimed.
Experts have discovered the levels of a particular type of DNA in a developing embryo are a crucial factor in whether a pregnancy will be successful and a simple test can be used to select the most viable embryos.
The development has the potential to revolutionise the success rate of fertility treatment, which currently stands at about 35 percent of IVF cycles resulting in a pregnancy. About 50 000 women undergo IVF treatment in Britain every year.
Clinical trials conducted in New York using the new technique, which was developed by researchers at Oxford University, resulted in a pregnancy success rate of around 80 percent.
Professor Dagan Wells, the Oxford specialist who led the research team, told the Press Association the test could be hugely beneficial for would-be parents who often face multiple disappointments and considerable expense going through repeated IVF treatment cycles.
It focuses on mitochondria, which plays a key role during the development of an embryo. The Oxford researchers found that some embryos have excessive levels of mitochondrial DNA - or mtDNA - and will consequently not produce a viable pregnancy. The new technique pinpoints embryos with levels of mtDNA below a certain threshold and selects them for implanting, resulting in the very high success rates seen in the New York trial.
Prof Wells said those undergoing IVF treatment face an uphill struggle because the majority of embryos created in the process of harvesting eggs and artificially fertilising them with sperm have “no chance at all” of becoming a baby.
The success rate for IVF is rising by about one percent a year but Prof Wells said that progress was “painfully slow” and a woman who, for example, produces eight embryos may have only one that will result in pregnancy. He said: “Any test of the embryo that will result in a baby is therefore highly desirable.”
Prof Wells said: “What we have found is that a significant number of embryos have unusually high levels of mitochondrial DNA. Having mtDNA above a certain threshold seems incompatible with implantation of an embryo.” Prof Wells said it is still unclear why the embryos produce too much mtDNA.
IVF: HOW THE NEW TEST WORKS
1 Patient injected with hormones to stimulate egg production
2 Eggs are collected from ovary
3 Eggs and spern are combined for fertilisation
4 Five-day-old embryos are used for the test. At this time embryos are made up of around 100 cells, of which five are removed for testing
5 New test involves usual chromosomal screening and testing for levels of mitochondrial DNA present so that embryos that fit the optimum threshold can be implanted, helping patients get pregnant quicker
The Independent