Scientists
believe they can double or even triple the proportion of healthy babies born as
a result fertility treatment with a relatively simple technique that takes a
series of time-lapse photographs of the developing IVF embryos.
On
average only about 24 per cent of IVF embryos implanted into women in the UK
lead to live births but the researchers believe this could be increased to 78
per cent using the new technique for selecting the best embryos.
“I
believe it is the most exciting breakthrough we've had in probably 30 years,”
said Professor Simon Fishel, managing director of the CARE Fertility Group,
where the technique was developed.
“Every
IVF practice in the world is unintentionally and unwittingly putting back into
the womb unviable embryos that don't make babies,” Professor Fishel said.
“We
hope to see a paradigm shift in terms of IVF. It's a game changer for everybody
to have such an uplift in live birth rates. This is the beginning of something
revelatory,” he said
Each
year, licensed clinics in Britain carry out about 60,000 IVF treatments but
most of them end in failure, causing immense emotional upset to couples, many
of whom have paid between £5,000 and £10,000 for each treatment cycle.
The
new procedure, which costs £750, identifies the best embryos to be implanted
into the womb based on the time it has taken to develop between two key stages
in the early life-cycle of the embryo.
Thousands
of time-lapse pictures are taken during the first few days of an IVF embryo's
life and these are used to identify the time between the first appearance of
the fluid-filled cavity, called the blastula, and the final moment before the
embryo “hatches” from its protective shell.
Scientists
have discovered that when this period lasts longer than about six hours, the
IVF embryo is likely to be carrying an abnormal number of chromosomes, called
aneuploidy, which will lead to a failure of the pregnancy.
A
preliminary study, published in the journal Reproductive Medicine Online and
based on a retrospective analysis of 88 IVF embryos of 69 couples, found that
the time-lapse technique could have improved the success rate of life births in
this particular group of patients from 39 per cent to 61 per cent.
Even
better success rates can be expected once the procedure is refined and applied
to the wider population of infertile couples seeking IVF treatment, Professor
Fishel said.
“Our
work has shown that we can easily classify embryos into low or high risk of
being chromosomally abnormal. This is important because in itself this is the
largest single cause of IVF failure and miscarriage,” he said.
“The
beauty of this technology is that the information is provided by a non-invasive
process. So far we have seen a 56 per cent uplift compared to conventional
technology, giving our patients the equivalent to a 78 per cent live-birth
rate,” he added.
Normally,
IVF embryos in an incubator are checked manually each day by embryologists but
the time-lapse cameras are able to do this automatically by taking pictures
every 10 minutes without interfering with embryo development, said Alison
Campbell, embryology director at Care Fertility in Nottingham, who developed
the computer algorithm controlling the analysis.
“With
time-lapse we have the ability to view more than 5,000 images over the same
time period to observe and measure more closely each stage of division and
growth. As a result of continuous monitoring we have demonstrated that delays
at defined points indicate abnormal development,” Ms Campbell said.
Martin
Johnson, a fertility expert and editor of the journal where the work is
published, said further “prospective” studies comparing the technique to
existing methods of embryo selection are still needed before the procedure is
recommended as standard treatment. “There are caveats with this research….and
for these reasons we have to be cautious,” he said.
Sue
Avery, director of Birmingham Women's Fertility Centre, said: “Unfortunately
the study does not compare this exciting new approach with standard practise in
embryology in which embryologists already look for the best embryos to place in
the womb. Until the new technique is compared to current practise we cannot
know whether different embryos are being chosen.”
Egg timing: Key stages
The
developing embryo (image one, above) goes through two key stages when the
fluid-filled cavity or “blastula” first forms (image two) and when the blastula
is fully formed before the embryo “hatches” (image three).
The
time between the two is used to judge whether the embryo is viable, with no
defects in chromosome numbers. If the period is longer than six hours, the
embryo is at high risk of abnormal chromosomes, which will inevitably lead to
complications. Time-lapse photographs can indicate which embryos have a shorter
time-period between these two points, and so which embryos are best for
implantation into the womb.
