Navigation Links
Nutrition a major factor in rise in twin pregnancies

The commonly held view that IVF is the only culprit in the steady increase in the numbers of twins born over the past thirty years was challenged by a scientist speaking at the 22nd annual conference of the European Society of Human Reproduction and Embryology in Prague, Czech Republic, Wednesday 21 June 2006. Professor Robert Jansen, Medical Director of Sydney IVF, Sydney, Australia, said that his research had shown that improved nutrition, both maternal and in the lab in the case of IVF, had produced better and stronger embryos.

"Over the last 100 years, both in the UK and Australia, there has been an increase in identical twinning through the division of the embryo into two, even without IVF", he said, "and with the move to single embryo transfer with IVF this trend is obviously set to continue." Professor Jansen went on to say that the present rate of identical twinning with IVF is between one-in-a-hundred and one-in-fifty, a little over twice the rate involved when getting pregnant naturally.

Professor Jansen and his team reviewed Australian national birth statistics from 1920 to 2003 to determine the sex of babies at birth among multiple pregnancies. They found that the rate of dizygotic (DZ) twinning ?where two embryos are involved and half the twins will be of different sex - was relatively constant from 1920 until the 1960s, but there was then the well-known dramatic increase with the advent of induced ovulation and IVF ?reaching 300 in every 1000 IVF conceptions by 2000. Among monozygotic (MZ) twins, caused by embryo division (so all are of like sex), the excess rate of same-sex twins among natural conceptions has risen steadily for the last 80 years. MZ twins were relatively rare among IVF babies in the 1980s ?much less than occurs naturally ?but then rose in the nineties to reach 14 per 1000 by the year 2000.

"As IVF techniques improved there was a steady and substantial increase in MZ twinning, but starting from a low bas e ?much lower than with natural conceptions", said Professor Jansen. "Our study shows for the first time that the increase we've seen coincides with improving culture conditions and that it started before any manipulation of the zona ?the 'shell' of the egg ?began. Transfer of just one embryo can therefore still lead to twins. If a higher rate of MZ twinning turns out to be a natural adaptation to improved nutrition or culture conditions, it could prove difficult to reverse as embryo quality continues to improve ?whether in the IVF lab or in the community generally."

"Because two implanted embryos have twice the chance of MZ twins than a single implanting embryo the best way of minimising MZ as well as DZ twinning is to transfer one embryo at a time, irrespective of the age of the mother to be", he said.

In another other presentation to the conference, Mr. Graham Scotland, from the Health Economics Research Unit, University of Aberdeen, Aberdeen, UK, described how he and his colleagues had conducted work that throws light on why some couples prefer double embryo transfer (DET), despite being aware of the risks of twin pregnancy. His team assessed patients' preferences for a range of adverse birth outcomes associated with twin pregnancies ?cerebral palsy, cognitive impairments, visual impairments, perinatal death ?as well as a scenario in which treatment failed and they did not become pregnant. Participants were asked to read several cards describing the treatment outcomes and then asked hypothetical questions to elicit their preference value for each.

"The results showed that many women awaiting IVF appear to prefer the prospect of a chronic adverse birth outcome rather than childlessness", said Mr. Scotland. "Having no child at all was valued significantly lower than having a child with physical, cognitive or visual impairments, but significantly higher than perinatal death. Our work suggests that couples may need to be convinc ed that their chances of live birth with single embryo transfer are as high as they would be with DET, before they will voluntarily accept it."


'"/>

Source:European Society for Human Reproduction and Embryology


Related biology news :

1. Columbia research lifts major hurdle to gene therapy for cancer
2. Researchers uncover sequence of major rice pathogen
3. Emergence of cancer as major cause of childhood death in developing countries is not being adequately addressed
4. Biochemists report discovery of structure of major piece of telomerase; implications for cancer
5. Virologists make major step towards understanding the process of HIV infection
6. Biota makes major antiviral discovery
7. New gene scanning technology marks a major advance in disease research
8. LIAI scientists make major finding on potential smallpox treatment
9. MicroRNAs have shaped the evolution of the majority of mammalian genes
10. MIT: Oceans are a major gene swap-meet for plankton
11. U-M scientists identify major psoriasis susceptibility gene
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/7/2017)...   HireVue , the leading provider of video ... best talent, faster, today announced the additions of ... Diana Kucer as Chief Marketing Officer (CMO). ... poised to drive continued growth in the company,s new ... record bookings in 2017. "Companies worldwide turn ...
(Date:3/2/2017)... YORK , March 2, 2017 Summary ... better understand Perrigo and its partnering interests and activities since ... ... Partnering Deals and Alliance since 2010 report provides an in-depth ... leading life sciences companies. On demand company reports ...
(Date:3/2/2017)... , March 2, 2017 Who risk ... lawsuits? Download the full report: https://www.reportbuyer.com/product/4313699/ ... THE FINGERPRINT SENSOR FIELD? Fingerprint sensors using capacitive ... The fingerprint sensor vendor Idex forecasts an increase of ... mobile devices and of the fingerprint sensor market between ...
Breaking Biology News(10 mins):
(Date:3/24/2017)... 24, 2017   Sienna Biopharmaceuticals, Inc. , a ... announced that Richard Peterson will join the ... Peterson, who brings more than two decades of ... who is retiring at the end of April but ... Peterson joins Sienna from Novan, Inc., where he served ...
(Date:3/23/2017)... ... March 23, 2017 , ... AxioMed president, Jake Lubinski, describes ... characteristics when deformed, which is identical to how the human discs work to ... and return to its natural state along a hysteresis curve, exactly like a ...
(Date:3/23/2017)... , Mar 23, 2017 Research and ... Global Markets" report to their offering. ... The Global Market ... Billion in 2016 at a CAGR of 8.9%, ... and non-energetic bioproducts into seven major product segments: bio-derived chemicals, ...
(Date:3/23/2017)... Mass. , March 23, 2017 /PRNewswire/ ... partner to global in vitro diagnostics manufacturers ... of the industry,s first multiplexed Inherited ... disease testing by next-generation sequencing (NGS). The ... were developed with input from industry experts ...
Breaking Biology Technology: