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Embryo screening linked to lower IVF success rates

10 July 2007
Appeared in BioNews 415

A technique used to select IVF embryos most likely to implant and develop could actually reduce success rates, according to a study by Dutch researchers. Preimplantation genetic screening PGS involves removing a single cell from an IVF embryo and testing it for the presence of chromosome aneuploidiesgenetic errors that would prevent normal development. The new findings, published in the New England Journal of Medicine and presented at the annual meeting of the European Society of Human Reproduction and Embryology (ESHRE), show that the use of PGS is associated with lower pregnancy and live birth rates.

PGS is distinct from PGD in which an embryo is tested for a single genetic disorder. The Human Fertilisation and Embryology Authority (HFEA) first licensed PGS in 2002, and the first reported UK birth following the use of this technique was in 2003. However, there is continuing disagreement over the utility and efficacy of PGS, with critics saying that its benefits are unproven, while supporters say that it improves the chances of a successful pregnancy in certain groups of patients.

In the latest study, a team of researchers from the Centre for Reproductive Medicine at the University of Amsterdam compared three cycles of IVF in 408 women aged between 35 and 41, 206 of whom had PGS included as part of the treatment. They found that both the pregnancy and live birth rates were lower in the PGS group. Lead author Sebastiaan Mastenbroek said: 'We found that, at 12 weeks, 52 of the women in the PGS group were pregnant (25 per cent), whereas 74 of the control group (37 per cent) had an ongoing pregnancy', adding 'the women in the PGS group also had a significantly lower live birth rate: 49 or 24 per cent, as opposed to 71 or 35 per cent, of the controls'.

The team says there could be several explanations for their results, including the possible effect of removing a single cell from the embryo, or the fact that not all chromosome abnormalities can be detected using PGS - so an apparently normal embryo may still harbour serious genetic errors.

Mastenbroek highlighted the increasingly widespread use of PGS in many IVF clinics. 'The idea of screening embryos for chromosomal abnormalities to increase live birth rates in IVF is very plausible, and women of advanced maternal age are willing to undergo any technique that may provide them with a baby', he said. He also said that more research was needed, particularly in other groups of women who are offered PGS, such as those who suffer recurrent miscarriage or repeated failure of IVF, since evidence for a benefit of PGS in these groups of women is currently still lacking.

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18 January 2016 - by Heidi Mertes, Sjoerd Repping & Guido de Wert 
Under the auspices of the Virtual Academy of Genetics, COGEN recently issued a 'consensus statement' on preimplantation genetic screening, based on a scientific meeting held in Paris last September...
21 July 2008 - by Alison Cranage 
The use of DNA chip (microarray) technology in embryo screening is to be investigated by an ethics task force from the European Society of Human Reproduction and Embryology (ESHRE). The technology has the potential to screen IVF embryos, in order to improve fertility treatment success rates. In...
16 June 2008 - by Alison Cranage 
The British Fertility Society (BFS) has issued new guidelines for the use of pre-implantation genetic screening (PGS) in patients undergoing fertility treatment. The new guidelines, published in the journal Human Fertility, state that there is no evidence that PGS improves pregnancy rates or decreases miscarriage rates for...
20 August 2007 - by Danielle Hamm 
A BBC investigation has found that women receiving IVF on the National Health Service (NHS) in the UK may have a lower chance of conceiving than private patients because treatment is not always provided at the most appropriate time. There is an optimal time to perform the...
17 July 2007 - by Dr Alan Thornhill 
Embryo selection following cleavage stage embryo biopsy and chromosome analysis to identify aneuploid embryos (those which have an abnormal number of chromosomes) in every couple having IVF/ICSI or all women of advanced maternal age is rightly considered by most clinics to be too invasive and potentially damaging for routine...
4 December 2006 - by Paul Scriven 
Make a habit of two things - to help, or at least to do no harm' (Attr Hippokrates of Kos). The principle of preimplantation testing for sporadic chromosome aneuploidy (preimplantation genetic screening, PGS) to improve the reproductive efficiency of assisted conception for couples at increased risk is a sound one. It...
20 November 2006 - by Professor Alan Handyside 
Ten years since the first reports of preimplantation genetic diagnosis for abnormal chromosome number, or aneuploidy, (now commonly known as PGS - preimplantation genetic screening), we are experiencing a prejudicial mistrust of a clinical approach that is generally accepted to be scientifically and clinically sound. Opponents of PGS frequently criticise its...
23 May 2005 - by BioNews 
Testing embryos for chromosomal abnormalities before they are returned to the womb can dramatically improve the 'take home baby rate' for some patients, according to a US fertility doctor. Speaking at the Sixth International Symposium on Preimplantation Genetics, held in London last week, Yury Verlinsky of the Reproductive Genetics Institute...
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