Breakthrough raises chances of 100 per cent success rate in IVF treatment

SCIENTISTS are developing a test that could dramatically boost IVF success rates from a single cycle of treatment.

The technique, from experts at Oxford University, checks for chromosomal abnormalities in the developing embryo, but also looks at two new markers that could potentially cause pregnancies to fail.

Over time, researchers hope to increase success rates towards the 100 per cent mark from just one cycle of IVF.

The scientific community is so excited by the novel technique that the study has won a prize from the US Society for Assisted Reproductive Technologies.

At present, only about 30 per cent of IVF cycles worldwide result in a pregnancy, with many failing due to chromosomal abnormalities.

Dr Dagan Wells’s team at Oxford has already pioneered a technique for checking embryos for these abnormalities.

Embryos are grown for five days in the lab and analysed to check the chromosome number.

Only healthy embryos are considered suitable for IVF transfer – increasing the chance of pregnancy to 70 per cent per cycle.

“The vast majority of embryos transferred worldwide have no genetic screening and 85 per cent of these fail to establish a pregnancy,” Dr Wells said.

“If you transfer to the uterus embryos that are confirmed to be chromosomally normal and develop well, reaching the blastocyst stage, the chance of producing a child is very high, about 70 per cent.

“But that still leaves 30 per cent that don’t make it. Why? We need a better understanding of the biology, allowing us to bridge that gap and approach 100 per cent success.”

The new technique combines the checking of chromosomes with the appearance of telo-meres, which cap chromosomes and are linked to healthy cells.

Another marker the test looks at is the number of mito- chondria – the power houses of a cell.

“Chromosomes are a big part of the story but they are not the be all and end all,” Dr Wells said.

“With the new tool we’ve developed we can count the chromosomes, but we can also look at telomeres, which protect the ends of chromosomes.

“This might be important, because longer telomeres are associated with the viability of the cell.”

The test will be particularly useful for older women, who have a higher chance of producing eggs with chromosomal defects, which can cause conditions such as Down’s syndrome.

However, it could also benefit younger women, maximising their chances of becoming pregnant in an IVF cycle.

The next stage of research – which will take about a year – will look in detail at the potentially negative effect of telomeres and mitochondria.

Dr Wells said experts needed to find the “shortfall” in why chromosomally healthy embryos do not always produce a baby.

“We hope to fill in the gap and get closer to getting a successful pregnancy from every IVF cycle,” he said.

“In the future, we will be able to compare embryos that make a baby and those that don’t, and we will be able to determine whether differences in their telomeres are responsible for unsuccessful IVF treatments that are currently unexplained,” Dr Wells said.

Once developed, the test is likely to add about £2,000 to the cost of IVF.