Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Freezing all embryos in IVF with transfer in a later non-stimulated cycle may improve outcome

04.07.2012
There is growing interest in a "freeze-all" embryo policy in IVF. Such an approach, which cryopreserves all embryos generated in a stimulated IVF cycle for later transfer in a non-stimulated natural cycle, would avoid any of the adverse effects which ovarian stimulation might have on endometrial receptivity during the treatment cycle. Ovarian stimulation has been shown to have adverse effects on endometrial receptivity and the risk of ovarian hyperstimulation syndrome (OHSS) is also increased when embryo transfer is performed in the stimulated cycle.

Freezing all embryos for later transfer might therefore improve implantation and pregnancy rates and increase the safety of IVF. Presently, the highest success rates in reproductive medicine are seen in the recipients of donor eggs. These are women who have not had ovarian stimulation - their endometrial tissue has not been exposed to high hormone levels, and they are not at risk of OHSS.

However, while the theory of a freeze-all policy seems attractive - and the technique has been commonly employed as a safety measure when OHSS is a threat - no robust systematic studies have indicated whether the cryopreservation of all viable embryos with later frozen embryo transfer (FET) is associated with better outcomes than fresh embryo transfers.

Now, the first meta-analysis on this subject indicates that the chance of a clinical pregnancy is around 30% higher when all embryos are frozen for later transfer than with fresh embryo transfer. The results were presented today at the annual meeting of ESHRE (European Society of Human Reproduction and Embryology) by Professor Miguel Angel Checa from the Hospital Universitari del Mar in Barcelona, Spain.

The study was a systematic review of the entire literature, which provided a pool of 64 relevant studies - with three randomised trials - performed before December 2011. The current review was based on information from 633 IVF/ICSI cycles in which 316 were randomised to fresh embryo transfer and 317 to FET. Results showed - based on a relative risk calculation - that the probability of a clinical pregnancy is significantly higher from freeze-all cycles than in fresh embryo transfers (a relative risk of 1.31, which was statistically significant). The miscarriage rates did not show significantly differences between the two groups.

"The pooled data demonstrates that embryo cryopreservation and subsequent FET may improve the outcome of assisted reproduction treatment," said Professor Checa. The study recorded an ongoing pregnancy rate of 38% in fresh transfer cycles, and 50% in the FET cycles.

Professor Checa also explained why FET in a later non-stimulated cycle might improve IVF results. He noted that the multiple eggs generated by ovarian stimulation will increase release of the hormone estradiol from the ovary, which affects the receptivity of endometrial tissue. In addition, some recent studies have shown that ovarian stimulation causes changes to the endometrial DNA pattern, which are not evident in the normal receptive endometrium.

Professor Checa added that the results of his study were "preliminary", but statistically robust. However, with other groups known to be performing similar studies, he urged patience until their results were known. "We are quite confident with our results," he said. "But in our view we should wait until the end of the year for results from other studies to confirm our data and recommend a change in IVF policy."

He added that, with improvements in the technologies of embryo cryopreservation (through vitrification), the evolution of freeze-thawed embryos in IVF is now comparable to that of fresh embryos. A freeze-all approach may thus extend that success even further - and with a greater degree of safety. "When we freeze all of the embryos, we completely avoid the risk of OHSS," said Professor Checa. "So freezing all the embryos we collect would avoid the biggest complication that exists in assisted reproduction."

From abstract no: O-169 Tuesday 3 July 2012, 15.30 hrs EEST

Fresh embryo transfer versus frozen-thawed embryo transfer in assisted reproduction technique cycles: a systematic review and meta-analysis

Note: When obtaining outside comment, journalists are requested to ensure that their contacts are aware of the embargo on this release.

The 28th Annual Meeting of ESHRE, the world's largest event in reproductive science and medicine, is taking place in Istanbul from 1-4 July 2012

Christine Bauquis | EurekAlert!
Further information:
http://www.eshre.eu

Further reports about: ESHRE FET Human Reproduction IVF embryo cryopreservation ovarian stimulation

More articles from Life Sciences:

nachricht Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University

nachricht Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017
25.04.2017 | Laser Zentrum Hannover e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>