Frozen embryos increase chance of successful IVF pregnancy
Treatment with 'fresh' embryos more likely to lead to premature births, new study claims
Steve Connor is the Science Editor of The Independent. He has won many awards for his journalism, including five-times winner of the prestigious British science writers’ award; the David Perlman Award of the American Geophysical Union; twice commended as specialist journalist of the year in the UK Press Awards; UK health journalist of the year and a special merit award of the European School of Oncology for his investigative journalism. He has a degree in zoology from the University of Oxford and has a special interest in genetics and medical science, human evolution and origins, climate change and the environment.
Tuesday 04 September 2012
Women who have fertility treatment with frozen embryos may have a better chance of success than those who use "fresh" ones, a study has found.
The findings represent a "major paradigm change" in assisted reproduction and could lead to a change in the current policy of preferring fresh embryos to frozen ones, scientists said.
A systematic review of more than 37,000 IVF pregnancies showed that there was a reduced chance of mothers bleeding and of babies being born prematurely with low birth weight when the embryos were stored and frozen compared with treatment involving freshly-transplanted ones.
The review of 11 international studies also found that the death rate immediately before and after birth was lower in babies who were born as a result of transferring frozen-thawed embryos into the womb compared with the transfer of fresh IVF embryos.
Scientists said the results should reassure mothers who intend to have IVF treatment with frozen embryos, but opinions are divided about whether the findings should lead to a change in the existing policy.
"If pregnancy rates are equal and outcome in pregnancies are better, our results question whether one should consider freezing all embryos and transferring them at a later date, rather than transferring fresh embryos," said Abha Maheshwari, a lecturer at the University of Aberdeen who led the study published in Fertility and Sterility.
"This represents a major paradigm change in assisted reproduction, and one which could satisfy the twin demands of optimising safety and success. Traditionally it has been thought that fresh is always better and used as a first choice," Dr Maheshwari said.
"Initially there were concerns about the safety of freezing techniques, and it was felt the quality of the embryo could deteriorate and impact on the health of the child. However, data to date has been reassuring," he told the British Science Festival in Aberdeen.
Current practice for most IVF clinics is that the best, fresh embryos are used first and only spare, good-quality embryos are frozen for transfer at a later stage. Freezing embryos has become more popular since single embryos have been transferred, rather than the riskier transfer of two or more embryos.
But Professor Alison Murdoch, head of the Newcastle Fertility Centre, said the findings of the review did not justify a change in existing policy.
"The results of individual studies that are considered in this meta-analysis are already being discussed in clinics and it is of some concern that conclusions have been drawn, incorrectly, that we should routinely freeze all embryos and transfer them in a future menstrual cycle," she said.
Peter Braude, a fertility specialist at King's College London, said the results of the study were counter-intuitive since "second-best" embryos are usually selected for freezing, with the best being transferred immediately.
- 2 Harry Potter fans can apply to the Hogwarts-inspired College of Wizardry
- 3 Jessica Chambers: 19-year-old woman 'doused with lighter fluid and burned alive' in the US
- 4 Russell Brand calls Nigel Farage 'poundshop Enoch Powell' in BBC Question Time debate
- 5 Orange Wednesdays are no more
Weather bomb in pictures: Storms cuts power for tens of thousands – and snow is on the way
Jessica Chambers: 19-year-old woman 'doused with lighter fluid and burned alive' in the US
Russell Brand calls Nigel Farage 'poundshop Enoch Powell' in BBC Question Time debate
Russell Brand was rendered speechless on Question Time by this man
Fury at Airbus after it hints the super-jumbo may be mothballed
Disgruntled RBS worker writes hilarious open letter to Russell Brand after anti-capitalist publicity stunt leaves him hungry
Nigel Farage defends Kerry Smith 'ch***y' comment: 'If you are going for a Chinese, what do you say you’re going for?'
Nigel Farage's approval rating hits 'record low' as popularity suffers in wake of Ukip sex scandal
Pakistan school attack live: Taliban kill at least 132 children in 'horrifying' massacre
Sony hack: Angelina Jolie branded 'seriously out of her mind' in further embarrassing leaked email saga
Panic Saturday: 13 million Britons spend £1.2bn – while 13 million others across the country live in poverty unable to afford food
£25000 per annum: Ashdown Group: IT Service Desk Analyst - Chessington, Surrey...
£16000 - £19000 per annum: Recruitment Genius: Our client is the UK's leading ...
£45000 - £55000 per annum + benefits: The Jenrick Group: Finance Manager/Manag...
£35000 - £38000 per annum: Recruitment Genius: This is a rare opportunity for ...