Scientists find new way to identify embryos that will implant in the womb

Fertility scientists have found a new way to identify embryos that will implant in the womb which could boost IVF success rates by up to 50 per cent, Daily Mail reported.

The presence of high levels of DNA from energy-producing cells in the embryo is a signal that it will fail to implant and produce a pregnancy, according to researchers from Oxford University.

They found a threshold, or cut-off point, below which embryos could be guaranteed to implant, and above which some failed to do so.

Each year in Britain, clinics carry out about 60,000 IVF treatments but many couples remain childless, often because the embryo fails to implant in the womb.

This can occur if the embryo is carrying genetic defects, or even if it appears to be healthy.

It is thought the new finding may explain around one in three implantation failures.

Most IVF clinics had success rates of 20-30 per cent of women having a baby after treatment.

This figure could rise to 40 per cent after pre-implantation genetic screening of the egg or embryo for chromosome abnormalities that are a major cause of miscarriages and conditions such as Down syndrome.

The good news is the new test is very easy to do, it only takes a couple of hours, and although they haven’t worked out a price yet it will be very cheap, just a few pounds.

The Oxford group investigated whether the amount of mitochondrial DNA found in early-stage embryos analysed in the laboratory affected the chances of it implanting after transfer to the womb.

Mitochondrial DNA (mtDNA) is genetic material found in the tiny power packs of the cells, or mitochondria, which is contributed by the woman.

The team of international experts led by Dr Fragouli took biopsies from 392 embryos at the five day stage of development when mtDNA levels start rising, generated by couples at eight clinics.

They also looked at 87 women aged around 38 where the embryo was transferred to the womb, resulting in 44 pregnancies and 43 failures to implant.

The findings showed high levels of mtDNA in embryos carrying genetic defects and those from older women, especially those over 40.

The team found healthy embryos capable of implanting in the womb tended to have lower levels of mtDNA than those failing to implant.

Most importantly, they could establish a threshold of mtDNA quantity below which implantation was certain.

Altogether 30 per cent of healthy embryos that failed to implant had quantities of mtDNA above this threshold, while 100 per cent of healthy embryos that produced a pregnancy had levels below it.

Dr Fragouli said it was not clear why high levels of mtDNA should affect implantation, although they are a sign that the embryo may be under stress.

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