An improvement in IVF (in vitro fertilisation) success rates. The study, presented at the annual meeting of the American Society for Reproductive Medicine (ASRM) last week, is published in the current issue of Molecular Human Reproduction.
Dr Dagan Wells and Professor Joy Delhanty, based at University College London, have developed a way to simultaneously examine all of the chromosomes present in a single cell taken from an early human embryo. Previously, only five of the 24 different types of human chromosome (referred to as 1-22, X and Y) could easily be identified in a single test. Dr Wells and Professor Delhanty studied 12 three-day-old IVF embryos, from which they examined a total of 64 single cells. They found that only three embryos had the correct number of intact chromosomes in every cell - nine contained at least one abnormal cell, and three had no normal cells at all.
Both natural and assisted conceptions have around a 20-25 per cent success rate per cycle, as the majority of human embryos are lost during very early embryo development. Dr Wells says that although having a small number of abnormal cells does not necessarily mean an embryo will fail to implant, or result in miscarriage, 'the chances of such an embryo forming a successful pregnancy are considerably less than those of a chromosomally-normal embryo'.
Fertility expert Lord Robert Winston called the work 'a very elegant approach' that increases our understanding of early human development, but says he is not convinced that it will be of practical benefit in improving IVF success rates. But according to the Sunday Times newspaper, fellow IVF specialist Dr Simon Fishel has already applied to the UK's Human Fertilisation and Embryology Authority for permission to use the technique in patient trials.
Sources and References
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Could chromosome analysis improve IVF success rates?
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Gene test planned to screen embryos
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Screening picks 'best-chance' embryos
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Most human embryos have the wrong number of chromosomes - now test-tube screening can spot them
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