Frozen embryos increase chance of successful IVF pregnancy

Treatment with 'fresh' embryos more likely to lead to premature births, new study claims

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.

Start your day with The Independent, sign up for daily news emails
Arts and Entertainment
Lou Reed distorted the truth about his upbringing, and since his death in 2013, biographers and memoirists have added to the myths
musicThe truth about Lou Reed's upbringing beyond the biographers' and memoirists' myths
News
people
News
Ed Miliband received a warm welcome in Chester
election 2015
Life and Style
Apple CEO Tim Cook announces the Apple Watch during an Apple special even
fashionIs the iWatch for you? Well, it depends if you want for the fitness tech, or the style
ebooks
ebooksA special investigation by Andy McSmith
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Project Implementation Executive

£18000 - £23000 per annum: Recruitment Genius: They work with major vehicle ma...

Recruitment Genius: Chiropractic Assistant

£16500 per annum: Recruitment Genius: A Chiropractic Assistant is needed in a ...

Recruitment Genius: Digital Account Executive - Midlands

£18000 - £26000 per annum: Recruitment Genius: They work with major vehicle ma...

Recruitment Genius: Web Developer

£28000 - £30000 per annum: Recruitment Genius: This company provides coaching ...

Day In a Page

NHS struggling to monitor the safety and efficacy of its services outsourced to private providers

Who's monitoring the outsourced NHS services?

A report finds that private firms are not being properly assessed for their quality of care
Zac Goldsmith: 'I'll trigger a by-election over Heathrow'

Zac Goldsmith: 'I'll trigger a by-election over Heathrow'

The Tory MP said he did not want to stand again unless his party's manifesto ruled out a third runway. But he's doing so. Watch this space
How do Greek voters feel about Syriza's backtracking on its anti-austerity pledge?

How do Greeks feel about Syriza?

Five voters from different backgrounds tell us what they expect from Syriza's charismatic leader Alexis Tsipras
From Iraq to Libya and Syria: The wars that come back to haunt us

The wars that come back to haunt us

David Cameron should not escape blame for his role in conflicts that are still raging, argues Patrick Cockburn
Sam Baker and Lauren Laverne: Too busy to surf? Head to The Pool

Too busy to surf? Head to The Pool

A new website is trying to declutter the internet to help busy women. Holly Williams meets the founders
Heston Blumenthal to cook up a spice odyssey for British astronaut manning the International Space Station

UK's Major Tum to blast off on a spice odyssey

Nothing but the best for British astronaut as chef Heston Blumenthal cooks up his rations
John Harrison's 'longitude' clock sets new record - 300 years on

‘Longitude’ clock sets new record - 300 years on

Greenwich horologists celebrate as it keeps to within a second of real time over a 100-day test
Fears in the US of being outgunned in the vital propaganda wars by Russia, China - and even Isis - have prompted a rethink on overseas broadcasters

Let the propaganda wars begin - again

'Accurate, objective, comprehensive': that was Voice of America's creed, but now its masters want it to promote US policy, reports Rupert Cornwell
Why Japan's incredible long-distance runners will never win the London Marathon

Japan's incredible long-distance runners

Every year, Japanese long-distance runners post some of the world's fastest times – yet, come next weekend, not a single elite competitor from the country will be at the London Marathon
Why does Tom Drury remain the greatest writer you've never heard of?

Tom Drury: The quiet American

His debut was considered one of the finest novels of the past 50 years, and he is every bit the equal of his contemporaries, Jonathan Franzen, Dave Eggers and David Foster Wallace
You should judge a person by how they peel a potato

You should judge a person by how they peel a potato

Dave Hax's domestic tips are reminiscent of George Orwell's tea routine. The world might need revolution, but we like to sweat the small stuff, says DJ Taylor
Beige is back: The drab car colours of the 1970s are proving popular again

Beige to the future

Flares and flounce are back on catwalks but a revival in ’70s car paintjobs was a stack-heeled step too far – until now
Bill Granger recipes: Our chef's dishes highlight the delicate essence of fresh cheeses

Bill Granger cooks with fresh cheeses

More delicate on the palate, milder, fresh cheeses can also be kinder to the waistline
Aston Villa vs Liverpool: 'This FA Cup run has been wonderful,' says veteran Shay Given

Shay Given: 'This FA Cup run has been wonderful'

The Villa keeper has been overlooked for a long time and has unhappy memories of the national stadium – but he is savouring his chance to play at Wembley
Timeless drama of Championship race in league of its own - Michael Calvin

Michael Calvin's Last Word

Timeless drama of Championship race in league of its own