US doctors report that they have helped five couples to have IVF babies which are able to provide tissue-matched cord blood for ill siblings. Four of the so-called 'saviour siblings' were conceived to help children with leukaemia, while another was born to help Charlie Whitaker, a British boy affected by Diamond-Blackfan anaemia. Scientists and clinicians at the Reproductive Genetics Institute in Chicago have now published details of the procedure, which involves genetic testing of embryos to establish their tissue type. The authors, who published their findings in the Journal of the American Medical Association, claim the technique has 'wide implications in medical practice'.
The Chicago doctors helped the Nash family conceive the world's first saviour sibling, a baby boy born in October 2000. Adam Nash provided umbilical cord blood stem cells used to treat his sister Molly, who was affected by a rare genetic condition called Fanconi's anaemia. The procedure involved testing IVF embryos to identify those which were both free from the disease, and also a tissue match for Molly. The five latest cases have sparked debate in the US, since all the embryos were tested solely for tissue type, and not for any genetic condition. Gilbert Meilander, a member of the President's Council on Bioethics, called the technique 'morally troubling'.
The doctors treated nine couples, who had existing children affected by acute lymphoid leukaemia, acute myeloid leukaemia, or Diamond Blackfan anaemia. After testing a total of 199 embryos, they identified 45 tissue-matched embryos for implantation. The team used 28 of these in 12 IVF cycles, which resulted in five singleton pregnancies. 'Screening embryos is still highly controversial and even not allowed in some countries, but it appears to be a reasonable option for couples', said the Institute's director Yury Verlinsky. The Whitaker family travelled to Chicago for treatment, after being refused permission to have the procedure carried out in the UK.
A new poll suggests that the majority of Americans support the use of preimplantation genetic diagnosis (PGD) for establishing tissue type only. A survey of 4005 people by the Genetics and Public Policy Center revealed that 61 per cent approve of using PGD to help an ailing sibling, while 33 per cent disapprove. By contrast, 57 per cent of respondents disapprove of using PGD to select embryos on the basis of sex. However, 80 per cent expressed concern that if not regulated, genetic technologies such as PGD could 'get out of control'. 'There is strong support for using these technologies when there is a health benefit, even when that benefit is for another person, but this support coexists with deep-seated worries about where all these new technologies may be taking us', said Center director Kathy Hudson.
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A survey of 561 American women undergoing treatment for infertility shows that 41 per cent would choose the sex of their baby, if sex selection was offered at no additional cost. However, it seems that any fears about sex selection causing gender imbalances are unfounded, say the researchers, as the women said they would choose boys and girls in almost equal numbers. The research is published in the March issue of the journal Fertility and Sterility.
Of the 561 women surveyed, 229 said they would choose to select the sex of their future child. Forty-five per cent of the women had no children and 48 per cent had children all of one sex. Of the women who said they would choose to select the sex of their child, 55 per cent would choose a sperm separation technique, while 41 per cent would choose preimplantation genetic diagnosis (PGD). Four per cent of the women said they would use neither technique. The research showed that women who had no children already were almost evenly split over whether they would choose boys or girls. In addition, women with only daughters would select a male child while women with only sons would select a female child. Half of the women who wanted sex selection at no cost said they would still choose to select the sex of their next child even if they had to pay.
Sex selection for non-medical reasons is controversial in the US and elsewhere. Both the International Federation of Gynecology and Obstetrics and the American College of Obstetricians and Gynecologists oppose its use and the President's Council on Bioethics has expressed concerns over the issue. However, the American Society of Reproductive Medicine (ASRM) has said that it supports sex selection for non-medical reasons such as family balancing, provided the methods used are proved to be safe and effective. In the UK, the Human Fertilisation and Embryology Authority (HFEA) ruled in 2003 that parents should not be allowed to choose the sex of their babies.
Lead researcher Tarun Jain, of the University of Illinois, Chicago, said that 'sex selection is a topic that's almost taboo for physicians to talk about', adding that 'prior to this study, there has been no data to indicate what the demand might be'. He continued: 'As the techniques gain more popularity, physicians will have to decide if they will offer the procedure to patients with and without children'. On the fear that sex selection would inevitably create a gender imbalance, Jain said the 'presumption is a preference for boys', adding 'but our study did not show that. In fact, in patients who did not have children there was no greater desire for boys over girls'.
The results of a study in Scotland have indicated that obese and overweight women have the same chance of successful IVF treatment as normal weight women. The research was undertaken in Aberdeen between 1997 and 2006, on 1,700 women undergoing their first cycle of IVF, and included overweight women, and women who were clinically and heavily obese. No marked difference was noted in the proportion of positive pregnancy tests, ongoing pregnancies and live births between any particular weight group. In addition, no further cost was incurred by women with a body mass index (BMI) of up to 35 (individuals with a BMI of over 25 are classed as overweight, while those over 30 are classed as obese).
However, the study showed that a higher proportion of women in the overweight and obese groups had a miscarriage and needed higher doses of drugs to stimulate their ovaries during their treatment. The higher rate of miscarriage echoes the findings of a study conducted last November by scientists at the Stanford University School of Medicine in California, US, which suggested that a mother's weight can affect the outcome of an otherwise normal pregnancy.
Leader of the study Dr Abha Maheshwari, a clinical lecturer in reproductive medicine at the University of Aberdeen, said that women with a BMI over 35 should not be offered IVF until they had lost weight because of the particularly high risk of complications. Professor Adam Balen, an expert in reproductive medicine at Leeds Teaching Hospitals agreed, saying that there is no doubt that obesity has a powerful effect on fertility. Balen also recognised that the risk of complications such as miscarriage and maternal or fetal death are more readily associated with obesity.
Dr Maheshwari had expected IVF costs to be higher in overweight and obese women, but the study showed that treatment should not be declined based on weight alone and that age was a much more relevant factor. The British Fertility Society recommends that no one with a BMI over 35 should receive IVF treatment, and women with a BMI over 30 should delay treatment until they have lost weight. Professor Balen, author of the Society's guidelines, emphasised that these were put together on clinical grounds, not cost grounds.
A UK fertility clinic has offered fifty couples the chance to take part in a trial of a 'modified form of IVF'. Following strict assessments, eligible patients will receive the treatment - including all drugs and 'the unique embryology and genetic testing' - for free. CARE Fertility centre in Nottingham says that the trial, if successful, could 'revolutionise' fertility treatment.
The new form of treatment involved in the trial aims to maximise the chances of a successful pregnancy by making sure that embryos transferred to the woman during treatment are the best - thereby minimising the rates of failed implantation and/or miscarriage. A similar study has already been undertaken in the US, which demonstrated greatly improved success rates and a reduction in the miscarriage rate. The implantation rate in the US study was above 70 per cent and the ongoing pregnancy rate was 'well over' 60 per cent - far higher than normal success rates for IVF.
According to information press released by CARE Fertility, about 70 per cent of human embryos do not go on to form successful pregnancies, both in natural and assisted conception. One of the major causes of embryo loss, says CARE Fertility, is chromosomal abnormalities within the embryos themselves, some of which may prevent correct development or implantation. Many of these chromosomal problems increase with the age of the mother.
Doctors and researchers from CARE Fertility have worked alongside US doctors and now plan to introduce the new IVF technique to the UK. The initial trial, which is already closed to applications, will begin later this year - but details of exactly what it will entail - other than some form of chromosomal testing - have yet to be released. Dr Simon Thornton, Medical Director of the CARE Fertility Group, said that 'until now, the selection of embryos has been very 'hit and miss' - the embryologists having to choose on how embryos look under the microscope'. He added that 'this unsatisfactory approach can now be replaced using new, exciting scientific methods to study the actual chromosomes which will provide an opportunity to double the current chances of IVF working'.
Dr Simon Fishel, Managing Director of Care Fertility, added that the US trial 'has given us great cause for optimism that at last we can conquer one of the great inefficiencies of IVF - the failure of a single embryo to make a baby more than 50 per cent of the time'. He added that 'we now believe this approach, if repeated at CARE Fertility in Nottingham, will change the way IVF is done and give couples even more opportunity for success - our goal has to be 'one embryo, one baby'. He told the Sun newspaper that he cannot disclose any details about the trial, adding that 'I can say that I am very, very excited about it'.
Lyon, France: Evidence gathered from time-lapse recordings of the formation of early embryos (blastocysts) in the laboratory has revealed why embryos created via IVF and undergoing extended culture are more likely to develop into twins than those created via natural conception. Furthermore, the research has shown that the culture in which the IVF embryos are formed is possibly responsible for the embryos dividing into twins.
Dianna Payne, a visiting research fellow at the Mio Fertility Clinic, Yonago, Japan, told the 23rd annual meeting of the European Society of Human Reproduction and Embryology today (Monday 2 July) that about three pairs of twins per thousand deliveries occurred as a result of natural conception, but many more were born after IVF, even when only one embryo had been transferred to the mother (approximately 21 pairs per thousand deliveries). However, it was not known why this happened.
Using 33 surplus frozen-thawed embryos that had been donated for research, Ms Payne and her colleagues used computer software called MetaMorph [1], which creates a free-running film from single images taken every two minutes with a digital camera attached to a microscope. They then used the software to analyse data from the film.
After thawing, 26 of the 33 embryos (most of which were composed of between two and ten cells) developed to blastocyst stage in which the blastocoele is formed. This is a fluid-filled cavity in the blastocyst and is formed on about day four or five when the embryo forms tight junctions between the cells around its periphery. These outer cells (the trophectoderm) begin to pump fluid into the blastocoelic cavity where a micro-environment is formed in which the cells that will go on to develop into the body of the embryo (the inner cell mass or ICM) develop.
The time-lapse recording showed that at this stage the blastocoele collapsed at least once in 25 of the 26 embryos (96%). “The frequency and degree of collapse varied, but the embryos that died tended to be those that had bigger and more frequent collapses,” said Ms Payne.
She explained the mechanism that underlies blastocoelic collapse and re-expansion. “The fluid in the cavity must be under positive pressure as this pressure is the motive force for expansion of the blastocyst. The trophectoderm maintains the pressure by pumping the fluid into the cavity. I believe that the collapses occur when some of the junctions between the cells fail – possibly due to localised cell death, or maybe due to a structural weakness in the junction itself – and the blastocoelic fluid leaks out. These collapses occur quite quickly – far more quickly than a pump could manage. The magnitude of the collapses is determined by the number of failed junctions. The greater the number of failed junctions, the more severe the collapse. In some cases the embryo cannot re-establish the junctions and the blastocyst is unable to re-expand and thus dies.”
Seventeen of the 33 embryos went on to become fully formed blastocysts and 11 either started to hatch or hatched completely from the zona pellucida (the gelatinous protective coating around the blastocyst).
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Fifteen embryos degenerated during culture and 11 of them did not re-expand after a collapse and subsequently degenerated. There was no evidence of embryo splitting during the hatching – which was one of the theories as to how twins were formed from a single blastocyst. However, two of the 26 embryos (8%) had two distinct ICMs and a third had a possible second ICM. The most common form of monozygotic twinning (identical twins resulting from the dividing of one embryo fertilised by a single sperm) is monochorionic/diamniotic, when two ICMs form before hatching.
Ms Payne said: “The second ICM was evident early in blastocyst formation in both embryos, and appeared to be the result of some ICM cells relocating and adhering to the opposite trophectoderm wall, seeded during an early collapse of the blastocyst. Both these embryos with two ICMs hatched completely.”
She continued: “Up until now, blastocyst collapse in the laboratory was thought to be a normal feature of blastocyst development. However, our findings that collapse was associated with degeneration of blastocysts as well as the formation of the second ICM suggest that these episodes in which blastocoele volume cannot be maintained may be an artefact of culture. Furthermore, our findings suggest that the formation of two ICMs during blastocyst development may be the cause of the high monozygotic rate after extended culture. This hypothesis fits well with the long established cause of the most common form of natural monozygotic twins.”
This research is, to Ms Payne’s knowledge, the first systematic study by time-lapse recording of blastocyst formation. It was time-consuming, with each recording taking up to five days, and required specialist equipment and knowledge. However, she said it should enable embryologists to work towards avoiding twin pregnancies during IVF. “This could be another tool in their armoury,” she said. “Those embryos that are at risk of twinning could be easily identified by counting the number of ICMs. Then, either a decision could be made about whether to transfer those embryos that are likely to give rise to twins, or, if the choice of embryos is limited, the mother could be prepared for the likelihood of twins and given appropriate clinical advice.”
In addition, more information about the cause of monozygotic twins could be collected in the future by a straightforward check of the numbers of placentas and sacs when the babies are born. The chorion and amnion are foetal membranes that contribute to the placenta and the foetal sac respectively. When twinning has occurred because two ICMs have developed (monochorionic/diamniotic twins) there is one placenta and two sacs, and these can be counted at birth.
“Careful recording of chorionicity and amnioticity of monozygotic twins at birth should shed further light on the effects of culture on embryos,” she concluded.
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The UK's Human Fertilisation and Embryology Authority (HFEA) has published a new edition of its 'Guide to Infertility'. The Guide contains details of all UK clinics that are licensed under the Human Fertilisation and Embryology Act 1990 to carry out in vitro fertilisation (IVF) and donor insemination (DI), although it does not contain information on other 'lower-tech treatments' that may be carried out by other doctors or hospitals.
For the first time, the Guide has also been produced as an online, interactive version in which patients may enter in their details and receive tailored information about services and clinics in their area and about particular treatments. It was assembled with the help of healthcare information experts 'Dr Foster' and produced and developed in consultation with patients and clinicians.
The Guide gives information about the causes of infertility and potential treatments, detailed information - including success rates - for 85 individual treatment centres, and 'real-life' patient stories. It shows that the average IVF success rate for women under 35 years old is 27.6 per cent, although some clinics have much higher success rates than others. The most common age at which a woman receives IVF is shown to be 35, but the chances of success decline with age, as the success rates in the Guide show.
The Guide also shows that the average waiting time for IVF treatment on the NHS varies greatly depending on the clinic. The shortest wait was two weeks, while the longest was 156 weeks. This has led critics to claim that NHS-funded IVF is still subject to a 'postcode lottery'. Longer waits for treatment come when the healthcare trust provides fewer funds for IVF - critics said this time difference could have a serious impact on some women's chances of success. Clare Brown, chief executive of Infertility Network UK said that some healthcare trusts must improve their provisions for fertility treatments. 'It is vital that people get treated as quickly as possible to make it a cost effective and clinically effective treatment', she said.
Public outrage over the IVF-conceived octuplets born in January to Nadya Suleman in California has led US legislators in Missouri and Georgia to propose laws that would limit the number of embryos a woman may have implanted when receiving a single fertility treatment. Georgia Senator Ralph Hudgens criticised Suleman's case, saying it is 'unforgiveable that she is unemployed and having 14 children on the backs of the taxpayers...' Supporters hope these measures will prevent rogue fertility clinics from unethically transferring a high number of embryos into women to increase their pregnancy success rates.
Critics argue that assisted reproduction is not an exact science and a blanket limit removes clinicians' flexibility to provide the best medical care. Dr Andrew Toledo, medical director of an Atlanta-based fertility clinic, warns that the measures are a 'cookie-cutter, one size-fits-all approach' and disregard important individual circumstances that determine the optimum number of embryos transferred for increased chances of pregnancy. Legal experts have voiced constitutionality concerns against the legislation impinging fundamental reproductive freedom and use of own genetic materials. A spokesman for the American Society of Reproductive Medicine (ASRM) specifically decried the Georgia bill as using the octuplets as 'an excuse to pass an extreme anti-abortion measure'. The Center for Genetics and Society called for a federal solution to prevent the state 'mishmash of policies' allowing patients to shop state-to-state for their desired treatment law.
The ASRM national guidelines recommend that a certain number of embryos be transferred depending on a woman's age and medical prognosis for successfully responding to IVF treatment. These recommend that women under 35 should have no more than two embryos transferred and women between 35 and 40 should have no more than three embryos transferred. Women over forty may have up to five embryos transferred during a single treatment due to their increased difficulty to conceive.
Missouri Republican Dr Robert Schaaf has tabled a measure that would convert these guidelines into state law. He acknowledges that it is a self-regulating industry wherein most specialists already comply with these standards, and the incidence of multiple-birth pregnancies has significantly decreased in the last decade. Still, he wishes that doctors be legally prevented from complying with patient requests to participate in harmful procedures as with Suleman, 33, who requested that five embryos be transferred despite the risks. California's medical board is currently investigating Suleman's fertility doctor and has proposed legislation empowering its Medical Board to supervise California-based fertility clinics.
The Georgia bill limits women under forty to having at most two embryos transferred and women over forty to three embryos maximum. The bill, titled The Ethical Treatment of Human Embryos Act, also outlaws the disposal of frozen embryos - similar to Louisiana law - and defines an embryo as a 'biological human being'. It was drafted by lawyers from the Bioethics Defense Fund, an anti-abortion and anti-embryonic stem cell research group and is supported by the Georgia Right to Life. Republican Senator Hudgens, who sponsored the bill for committee review last Thursday, denied it impacts on abortion and claims it only aims to prevent 'what happened in California from happening in Georgia'.
Suleman's story also attracted international fascination and highlighted the relevance of an ongoing UK debate that ultimately has led to the Human Fertilisation and Embryology Authority, the government's fertility watchdog, rolling out a new multiple birth policy that strongly encourages single embryo transfer (SET) where medically appropriate. The HFEA wrote a letter at the end of February to the NHS Directors of Public Health outlining the importance that individual clinics devise consistent policies of their own implementing the HFEA policy initiative for each clinic to reduce its annual percentage of multiple birth rates over three years to a target 10 per cent from a 24 per cent limit in 2009.
Highlights From The Conjoint Meeting Of The American Society For Reproductive Medicine And The Canadian Fertility And Andrology Society 19 October 2005
Montreal, Quebec- Even embryos formed from the eggs of healthy young donors exhibit a startlingly high number of abnormalities. Researchers presented work today at the conjoint meeting of the American Society for Reproductive Medicine and the Canadian Fertility and Andrology Society focusing on the use of Preimplantation Genetic Diagnosis (PGD) for embryos created with donor eggs .
PGD is used to increase the chances of pregnancy resulting from an IVF cycle and to prevent the transfer of embryos with identifiable genetic defects. It is recommended for women who have experienced recurrent pregnancy loss, women of advanced maternal age, those who have had previous failed IVF attempts with embryos of good appearance and couples seeking to avoid passing on a heritable disease. Up until now, all information on rates of chromosomal abnormality in embryos has come from infertility patients and those who know they carry a genetic disorder
Hypothesizing that routinely using preimplantation genetic diagnosis for chromosomal abnormalities would improve conception rates in donor egg IVF cases, researchers from the Huntington Reproductive Center in Pasadena, California evaluated 289 embryos from 22 egg donors in 26 fresh and two frozen embryo transfer cycles. They found that 46% of the embryos were chromosomally normal and 42% were abnormal. Only normal embryos were transferred to gestational surrogates on the fifth day after fertilization with an average of 2.4 embryos transferred per cycle. Sixty-four percent of the transfers resulted in an on-going pregnancy. The average age of the donors providing the eggs was 25.8 (all the donors were under 30) but interestingly, the donors? abnormal embryo percentages varied widely from 29% to 83% and it was impossible to tell from the appearance of the embryos which would test normal and which abnormal.
Dr William Kearns and his colleagues at the Shady Grove Fertility Reproductive Science Center in Rockville, MD, sought to determine the incidence of embryonic aneuploidy among the general population. They therefore examined a series of donor egg IVF cases, thus eliminating from consideration the major groups for which PGD is recommended- couples with a history of failed IVF cycles and women of advanced maternal age. They looked at 13 couples who had decided to engage an egg donor due to poor outcomes of their prior therapies. The 13 couples had 14 cycles with a total of 159 embryos examined. The donors? average age was 26.6 (21-31 range). Fifty-two percent of the embryos were found abnormal; 6% could not be diagnosed. All 13 patients had an embryo transfer with clinical pregnancy resulting for eight of the 13 patients. Pregnancy rates among the patients in this group were similar to those in patients using donor eggs who do not use PGD.
At Reproductive Biology Associates in Atlanta, GA, researchers investigated the differing incidence of aneuploidy in young infertility patients as compared with older patients and found that the frequency of chromosomally abnormal embryos is unexpectedly high in those of young reproductive age. In a prospective on-going study, 36 infertile patients (average age 32.5, all under 35), with no prior treatment and representing all diagnoses of infertility proportionally, had IVF with PGD. Their PGD results were compared with a control population of women over 38 (average age 40.7) who were undergoing IVF at the same time. Young patients in the study population had an average of 17.6 eggs retrieved, of which 70% fertilized; the older control patients had 13.5 eggs on average, of which 69% fertilized. The younger women in total had 103 embryos identified as normal and 198 abnormal embryos. The older women had, as expected, a higher proportion of abnormal embryos: 323 abnormal to 116 normal. Of the younger patients, 56% became pregnant, while 33% of the older patients became pregnant.
Eric Surrey, MD, President of SART, remarked, ?PGD may become a very useful technique for maximizing the chances of success of a particular cycle of IVF. And these results do shed light on some of the reasons why a particular young donor or patient might produce many eggs, which fertilize and develop as embryos of normal appearance, but do not result in pregnancy. However, PGD, especially using a single cell, is not fail-safe. Mosaicism, the presence of normal and abnormal cells in the same embryo can confound the results of single-cell PGD.?
The European Society of Human Reproduction and Embryology (ESHRE) has suggested that the recent expansion of the European Union (EU) could lead to a rise in UK and other western European couples travelling to eastern Europe for fertility treatment. Data revealed at the ESHRE annual conference in Berlin, Germany, shows that the availability of assisted reproduction techniques (ARTs) in eastern European countries that have newly joined the EU is similar to that in the west of Europe, but the cost of treatment is generally much lower.
Dr Anders Nyboe Andersen, of the Rigshospitalet at Copenhagen University in Denmark, presented preliminary data from the ESHRE European IVF Monitoring Programme for 2001 at the conference. This showed that some eastern European countries are performing more fertility treatments than western nations and some are achieving success rates for IVF and intracytoplasmic sperm injection (ICSI) that are as good as the highest success rates in the west.
Denmark was shown to have the highest availability of fertility treatments in Europe - as it had for the previous years' statistics - with 1,923 cycles performed per million citizens in 2001. The UK performed only 593 cycles per million, which was similar to the number carried out in Hungary (578 cycles per million). Slovenia, another eastern European country recently admitted to the EU, ranked fifth overall, with 1122 cycles per million. In the UK, where there is limited availability of IVF on the National Health Service, the average cost of one private IVF cycle is over ?2000, and often closer to ?4000, but in Hungary and Slovenia the cost could be much lower, as the price of the drugs used is cheaper. Additionally, while the pregnancy rate for IVF per embryo transfer in the UK is around 28.4 per cent, it is 36.2 per cent in Slovenia and 31.9 per cent in Hungary.
Europe-wide data should continue to be collected, said Professor Karl Nygren, co-author of the report, to ensure that potential patients have 'accurate and complete' information about the discrepancies between treatment availability and success rates in various countries. He added that the enlargement of the EU 'means that it is vital that potential patients can compare not only prices, but also the quality and efficacy of the treatments on offer'. When asked what he thought about people travelling to other countries for cheaper treatment, he responded 'we see fertility tourism as a negative sign that shows something is not functioning in your own country', but he warned that couples should think very carefully before travelling for IVF, as 'experience of coping in a foreign country far from home and family could be highly stressful'.
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A study by researchers at University Hospital in Gothenburg, Sweden, have found that stress and anxiety do not affect the chances of a woman getting pregnant while receiving fertility treatment.
Out of 166 women who answered the initial questionnaire, 139 women had embryos available for transfer during the study. Fifty-eight women got pregnant while 81 did not. The woman's state of mind, as assessed by the initial questionnaire and then a second questionnaire immediately before her eggs were retrieved, made no difference as to whether she became pregnant or not. The researchers saw similar pregnancy rates in women reporting anxiety and depression and women who did not. The number of good quality embryos was the only variable linked to getting pregnant.
The questionnaire used in the study was the Psychological General Well-Being (PGWB) index. This measures the women's emotions, general health, relationship with their partners, lifestyle, outlook on life and the intensity of their desire for a child. The initial questionnaire was given before the women started treatment. The second questionnaire was administered just before egg retrieval because patients often express worry and anxiety at this point. Since questions were asked before the embryo transfer, the answers given could not be influenced by whether the treatment had been successful or not. However, it did not guarantee women answered truthfully, and did not give answers that were more positive than they felt.
Past research does not agree as to whether stress and anxiety contribute to failure to achieve a pregnancy. Some studies suggest they do, and women have been cautioned it could hurt their chances of becoming pregnant. Though this study does not provide a definite answer, it does, due to its size and design, lend weight to the idea that stress and anxiety do not decrease a woman's chance of getting pregnant. Dr Lisbeth Anderheim, lead author of the paper, published in the journal Human Reproduction, stated, 'we can use these findings to reassure women, and this information should, in itself, help to reduce their stress and worry'.
Though stress may not be linked to the outcome of IVF, it is a 'very real factor throughout the infertility process and the psychological and emotional distress caused affects every part of a couple's life', according to Infertility Network UK, a national organisation providing help and support to infertility sufferers.
Lyon, France: Evidence gathered from time-lapse recordings of the formation of early embryos (blastocysts) in the laboratory has revealed why embryos created via IVF and undergoing extended culture are more likely to develop into twins than those created via natural conception. Furthermore, the research has shown that the culture in which the IVF embryos are formed is possibly responsible for the embryos dividing into twins.
