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How the latest IVF technique works

The latest development in IVF technology enables doctors to screen embryos before selecting which ones will be implanted in the womb, giving the fertility treatment a greater chance of succeeding.

Success rates for In Vitro Fertilisation (IVF) are currently about 30pc but could rise as high as 75pc with the new techniques being used by doctors.

The procedure involves examining sample cells from a five or six-day-old IVF embryo and checking each has the correct number of chromosomes, 23.

This allows doctors to screen out embryos which have one too many or too few chromosomes – a common problem which is thought to be the cause of six out of seven miscarriages.

The fault – called aneuploidy – is thought to be the main barrier that has prevented IVF success rates rising above 30pc.

Even those embryos that survive with the wrong number of chromosomes are born with genetic problems such as Down's Edwards' and Patau syndrome.

By examining each of the 23 pairs of chromosomes, doctors can select the embryos least likely to be aborted and reduce the risk of a baby being born with a genetic fault.

The second stage of the new technique involves comparing the embryo's chromosomes with the DNA of its parents, so that doctors can more easily identify genetic faults.

This "parental support" provides an extra layer of screening that helps boost the chance of successful fertilisation to 75pc.