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New study indicates safety of freezing eggs

23 June 2008
Appeared in BioNews 463

Research published last month in the journal Reproductive BioMedicine Online indicates that a new freezing technique to store human eggs is safe. The study, led by Dr Ri-Cheng Chian, of McGill University, Montreal, Canada, looked at children conceived using eggs frozen by vitrification, and showed that the rate of birth defects was the same as in natural or IVF pregnancy. The study may lead the way for women to freeze their eggs to postpone motherhood.

Vitrification involves removing water from the eggs, adding an agent that acts as an 'anti-freeze', followed by very rapid cooling. This process avoids ice crystals forming which can damage the egg's structure. When this is done, 95 per cent of eggs survive the thawing process compared to 50-60 per cent of eggs frozen using previous techniques.

The new study looked at 200 children born after the technique was used, and found that only 2.5 per cent had birth defects, which is comparable to rates in natural or IVF pregnancy. The average birth weight was also no different in children conceived using vitrified eggs compared to children conceived naturally or using IVF. The freezing of eggs is not currently routinely available, as the freezing of sperm and embryos is, due to safety fears.

A woman's fertility rapidly declines after the age of 35, and there are both social and medical reasons why women may wish to freeze their eggs before this time, for later IVF treatment. Social reasons include wanting to delay motherhood to develop a career, or find the right partner. In addition, the freezing of eggs may be more acceptable to those who have ethical objections to freezing embryos. Medical reasons for freezing eggs include doing so before facing treatment that may reduce fertility, such as cancer therapy.

Currently this is the only large-scale study looking at the effects of vitrification on birth defects. Dr Allan Pacey, secretary of the British Fertility Society (BFS), said that more, similar studies are needed to verify the safety of the technique.

Advanced egg-freezing technique as safe as IVF, research shows
The Times |  17 June 2008
Egg-freezing technique 'is safe'
BBC News Online |  17 June 2008
Egg freezing will allow more women to put off motherhood
The Daily Telegraph |  17 June 2008
Obstetric and perinatal outcome in 200 infants conceived from vitrified oocytes
Reproductive Medicine Online |  05/08
9 February 2009 - by Dr Will Fletcher 
The UK's Royal College of Obstetricians and Gynaecologists and the British Fertility Society have released a joint statement expressing serious concerns about women who freeze their eggs for non-medical reasons such as pursuit of their career. The success rate for pregnancies involving eggs that were frozen is...
17 November 2008 - by Alison Cranage 
Three new independent studies have provided further evidence that embryos stored using slow-freezing techniques may be better than fresh for IVF. The studies were presented at the American Society for Reproductive Medicine conference in San Francisco, US, last week. The studies indicate that using frozen embryos rather...
3 November 2008 - by Dr Peter Hollands 
The recent correspondence on egg vitrification in BioNews (1,2), prompts me to wonder if the pioneering research spirit that started the IVF industry sometimes gets a little carried away in the reality of patient care. At the start of the IVF industry the players were researchers and academics, and new...
23 October 2007 - by Dr Kirsty Horsey 
US fertility doctors have issued new guidelines recommending that women should not be able to freeze their eggs if there are no health indications for doing so. Women who are worried about not finding the right partner or who deliberately delay having children should not be...
3 September 2007 - by Ailsa Stevens 
Healthy British women can now to choose to freeze their eggs, giving them the opportunity to delay motherhood without risking pregnancy complications, according to the Sunday Times. The new service, aimed at career women and those waiting for the right partner, will be launched nationwide next month...
30 October 2006 - by Antony Starza-Allen 
By Antony Blackburn-Starza: A study presented at the annual American Society of Reproductive Medicine conference, which looked into the psychological motivations of women choosing to freeze their eggs for social reasons, showed that 40 per cent were prepared to be single mothers using their frozen eggs. Study leader Alan Copperman...
11 September 2006 - by Melanie Davies 
There is a steady and continuing trend towards later childbearing in all Western European countries. In England and Wales, the fertility rate for women in their thirties has now overtaken that for younger women. Over the last three decades, the average age of women having their first baby has risen...
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