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Chromosome screening may increase IVF success in older mothers

29 October 2012
Appeared in BioNews 679

Using a new IVF technique could considerably increase older women's chances of pregnancy, a small clinical trial presented at a fertility conference suggests.

In the technique embryos produced via IVF are first tested for major genetic abnormalities using a method called comprehensive chromosomal screening (CCS). For this, samples are taken from embryos at the blastocyst stage, when they have around 100 cells.

CCS tests whether embryos have the normal 46 chromosomes, 23 from each parent. The genetically normal embryos are cryopreserved for a month or two before being thawed and inserted in the womb. The cryopreservation period is thought to allow the woman’s hormones to settle after the disturbance caused by IVF drug treatment.

A randomised controlled trial in 60 patients compared the new technique against standard embryo screening, where embryo quality is assessed primarily by evaluating their appearance under a microscope.

The study was presented at a meeting of the American Society for Reproductive Medicine (ASRM) in San Diego, USA. Although the abstract relating the findings is unclear, the Telegraph says that the CCS technique 'took the successful pregnancy rate in a group of 38 to 42-year-olds from 33 to 61 percent'.

The researchers also reported that none of the women implanted with embryos that had been through CCS had first trimester miscarriages, whereas six of the 30 women implanted with embryos that had been through standard screening did miscarry within the first trimester.

Talking to the Telegraph, study co-author Dr Mandy Katz-Jaffe from the Colorado Centre for Reproductive Medicine, said: 'What we've been able to show is that a woman aged 38 to 42, if she has a blastocyst with a normal number of chromosomes, her chances of implantation are independent of her age. So she has the same chances of implantation – at 60 percent – as a woman who is 32'.

The risk of producing an embryo possessing an abnormal number of chromosomes (a condition known as aneuploidy) increases as a woman ages. By the age of 40, 75 percent of a woman's embryos are aneuploid, and this heightens the risk of any resulting child having disorders like Down's syndrome and also increases the risk of miscarriage.

The Telegraph reports that 'clinics in the USA, Australia and Spain are hurrying to adopt the techniques but in Britain only a tiny fraction of IVF patients is benefiting'.

Speaking to the newspaper, Dr Dagan Wells, a geneticist who helped pioneer embryo screening, and who was not involved in this study, said that if the results were confirmed, standard IVF practices in the UK would have to be 'completely re-evaluated'.

'I think the evidence is starting to mount up that chromosome screening may be ready for prime time', he added. 'CCS could potentially represent a revolution in the way IVF is done and infertility is treated'.

However, Mr Stuart Lavery, a consultant gynaecologist at the Hammersmith Hospital in London, told the Daily Mail that CCS is 'controversial. To put an embryo through the freeze and a thaw is a bit of an insult. It's a shock, and sometimes it will kill a few cells'.

Dr Linda Giudice, president-elect of the ASRM, said that the next step in assessing the new technique 'will be large scale trials including data from birth outcomes'.

Comprehensive Chromosomal Analysis Shown to Improve IVF Outcomes
American Society for Reproductive Medicine (press release) |  22 October 2012
Comprehensive chromosome screening (CCS) with vitrification results in improved clinical outcome in women >35 years: a randomized control trial
American Society for Reproductive Medicine (subscription required) |  22 October 2012
Doctors may have unlocked secret of IVF success for older mothers
Telegraph |  22 October 2012
New IVF screening can turn fertility clock back 10 years by only picking embryos most likely to develop healthy
Mail Online |  22 October 2012
25 November 2013 - by Ari Haque 
A report from the Office for National Statistics (ONS) shows that the number of multiple births among women over 45 has increased by 23 percent in the past year. The increase is thought to be in part due to more older women using IVF treatment to conceive...
8 July 2013 - by Siobhan Chan 
A 'powerful' form of genome analysis could improve embryo selection for IVF, according to scientists who report that the first baby has been born from this method...
12 November 2012 - by Dr Gillian Lockwood 
After a decade of claiming that the technique was only applicable to young cancer patients whose treatment would render them prematurely infertile, the American Society for Reproductive Medicine (ASRM) has decided that vitrification and warming of unfertilised oocytes followed by fertilisation by ICSI results in acceptable subsequent pregnancy rates...
8 May 2012 - by Ana Pallesen 
An IVF test which checks whether embryos carry the correct number of chromosomes could improve the chances of a successful pregnancy, a clinical trial suggests. The test – developed by the biotech company Blue Gnome – is used five days after an egg has been fertilised and helps doctors select which embryos should be implanted during IVF treatment...
31 January 2012 - by Ayesha Jadoon 
A new method of looking for chromosomal abnormalities in embryos can increase the chance of successful IVF implantation, a recent study in the journal Fertilisation In Vitro has shown....
8 May 2006 - by Dr Kirsty Horsey 
By Dr Kirsty Horsey: According to new figures, more than 20 IVF babies are born to women aged over 50 each year in the UK. In 2002, 96 women older than 50 were treated at fertility clinics across the country, according to the latest figures released by the Human Fertilisation...
19 September 2005 - by BioNews 
An editorial by three London-based senior clinicians in the British Medical Journal (BMJ) warns women about 'leaving it too late' to start a family. Susan Bewley, consultant obstetrician at Guy's and St Thomas'; Melanie Davies, consultant obstetrician and gynaecologist at the Elizabeth Garrett Anderson Hospital at University College Hospital and...
13 October 2003 - by BioNews 
The likelihood of IVF success could be down to the length of a woman's telomeres - the segments of DNA that make up the ends of chromosomes - reports Nature magazine. US scientists, based at the Tufts-New England Medical Center in Boston, have shown that women whose eggs have shorter chromosome tips...
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