Featured Research

from universities, journals, and other organizations

Single Thawed Embryo Transfer After PGD Does Not Affect Pregnancy Rates

Date:
July 10, 2009
Source:
European Society of Human Reproduction and Embryology (ESHRE)
Summary:
Transferring just one embryo at a time to a woman's womb after embryos have undergone preimplantation genetic diagnosis (PGD) and freezing at the blastocyst stage has become a real option after researchers achieved pregnancy rates that were as good as those for blastocysts that had not had a cell removed for PGD before freezing. Their results mean that it will be possible to reduce the number of multiple pregnancies after PGD and the consequent complications associated with these pregnancies.

Transferring just one embryo at a time to a woman’s womb after embryos have undergone preimplantation genetic diagnosis (PGD) and freezing at the blastocyst stage has become a real option after researchers achieved pregnancy rates that were as good as those for blastocysts that had not had a cell removed for PGD before freezing. Their results mean that it will be possible to reduce the number of multiple pregnancies after PGD and the consequent complications associated with these pregnancies.

The research was presented at the 25th annual meeting of the European Society of Human Reproduction and Embryology in Amsterdam and published online in Human Reproduction, simultaneously on June 30.

Dr Yacoub Khalaf, director of the assisted conception unit at Guy’s and St Thomas’ Hospital, London (UK), told the conference: “To the best of our knowledge, our study is the first to provide reassurance that a strategy of elective single embryo transfer in good prognosis patients seeking PGD, backed by an efficient PGD cryopreservation service, can result in pregnancy rates that are comparable to those for non-biopsied embryos that are frozen as part of conventional fertility treatment. These results should empower fertility centres to include PGD cycles for inherited genetic disorders in their efforts to reduce the multiple pregnancy rates after various forms of assisted conception treatment. Given the increasing number of PGD cycles performed each year, the advantage of widespread application of this policy would be considerable.”

Until now, fertility specialists have not applied a single embryo transfer policy to PGD for inherited genetic disorders because of concerns about how well biopsied embryos survive after freezing and thawing. “It was thought that the effect of the biopsy might reduce the embryos’ tolerance to freezing. This concern was not based on any scientific evidence, only on observations of low survival rates of biopsied frozen embryos,” said Dr Khalaf.

From January 2006 to July 2008 Dr Khalaf and his colleagues offered single embryo transfer together with freezing of surplus blastocysts to couples seeking PGD for single inherited genetic disorders such as cystic fibrosis. All the embryos were biopsied for the purposes of PGD on the third day after fertilisation, which is the time that they start to divide. Healthy embryos were cultured in the laboratory for a further two to three days to check that they were capable of reaching the next appropriate stage of development – the blastocyst stage. At this point, 32 couples who had two or more embryos that had successfully reached the blastocyst stage were offered the option of having one transferred to the womb and the rest frozen.

The researchers compared the pregnancy outcomes from a subsequent 32 frozen-thawed PGD cycles in these couples with the pregnancy outcomes from a control group of couples where 191 cycles of conventional IVF/ICSI were carried out using embryos that were frozen and thawed before implantation, but not biopsied at any stage.

They found that the blastocyst survival rate after thawing was similar between the PGD and IVF/ICSI groups (87% versus 88% respectively). There was no significant difference in the implantation and clinical pregnancy rates (35% versus 29% and 34% versus 36% respectively). The overall ongoing pregnancy rate for all frozen cycles (PGD and IVF/ICSI) was 34%, which compares favourably with the UK national average for frozen cycles (currently 18% live birth rate per thaw).

When the same period was compared with the period before the single embryo transfer policy was introduced for PGD couples, the multiple pregnancy rate in the cycles of fresh PGD dropped from 36% to 10% with no reduction in pregnancy rates.

Dr Khalaf said: “This research suggests that responsible clinical decisions do not have to come at the expense of reducing effectiveness of treatment. You can be responsible and maintain the chances of success for your patients by good clinical judgment and using the appropriate techniques.

“For patients, this provides reassurance that a couple’s chance of having a healthy child is not reduced by replacing only one blastocyst and freezing the surplus ones. Those frozen blastocysts do have a very good chance of leading to a healthy pregnancy too, and, therefore, patients will not feel pressurised to have more than one embryo replaced (with the increased risk of multiple pregnancies) in order to make use of their biopsied, unaffected embryos for which, otherwise, they might have little use. Now, these frozen blastocysts offer them the chance of an additional healthy pregnancy without having to go through the whole treatment cycle again.”

The first author of the paper in Human Reproduction, Dr Tarek El-Toukhy, a consultant in reproductive medicine and PGD at the assisted conception unit at Guy’s and St Thomas’ Hospital, said: “This study represents a continuation of our efforts to advance IVF and PGD safety through single blastocyst transfer and embryo freezing.”


Story Source:

The above story is based on materials provided by European Society of Human Reproduction and Embryology (ESHRE). Note: Materials may be edited for content and length.


Cite This Page:

European Society of Human Reproduction and Embryology (ESHRE). "Single Thawed Embryo Transfer After PGD Does Not Affect Pregnancy Rates." ScienceDaily. ScienceDaily, 10 July 2009. <www.sciencedaily.com/releases/2009/06/090630075305.htm>.
European Society of Human Reproduction and Embryology (ESHRE). (2009, July 10). Single Thawed Embryo Transfer After PGD Does Not Affect Pregnancy Rates. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2009/06/090630075305.htm
European Society of Human Reproduction and Embryology (ESHRE). "Single Thawed Embryo Transfer After PGD Does Not Affect Pregnancy Rates." ScienceDaily. www.sciencedaily.com/releases/2009/06/090630075305.htm (accessed October 20, 2014).

Share This



More Health & Medicine News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Nigeria Beat Its Ebola Outbreak

How Nigeria Beat Its Ebola Outbreak

Newsy (Oct. 20, 2014) The World Health Organization has declared Nigeria free of Ebola. Health experts credit a bit of luck and the government's initial response. Video provided by Newsy
Powered by NewsLook.com
Another Study Suggests Viagra Is Good For The Heart

Another Study Suggests Viagra Is Good For The Heart

Newsy (Oct. 20, 2014) An ingredient in erectile-dysfunction medications such as Viagra could improve heart function. Perhaps not surprising, given Viagra's history. Video provided by Newsy
Powered by NewsLook.com
Ebola Worries End for Dozens on U.S. Watch Lists

Ebola Worries End for Dozens on U.S. Watch Lists

Reuters - US Online Video (Oct. 20, 2014) Forty-three people who had contact with Thomas Eric Duncan, the first person diagnosed with Ebola in the U.S., were cleared overnight of twice-daily monitoring after 21 days of showing no symptoms. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Beijing Marathon Runners Brave Hazardous Air Pollution

Beijing Marathon Runners Brave Hazardous Air Pollution

AFP (Oct. 19, 2014) Tens of thousands of runners battled thick smog at the Beijing Marathon on Sunday, with some donning masks as the levels of PM2.5 small pollutant particles soared to 16 times the maximum recommended level. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins