FET

[bows&ribbons]

Part of me feels like i should listen to my doc who is a head re in this field and just do a fet since that is what is working for him..but part of me feels like i should try fresh if i can and freeze the rest (if i am so lucky to have more than one embryo to transfer). Are there any studies suggesting that babies resulting from frozen embryos are at an increased risk for abnormalities etc? Thanks! Do you know of any links to the safety of FET?
Thanks!

[Carole]

Dear bows&ribbons,
Here is a nice summary of concerns that have been raised about FET safety, almost all of which have been shown to be unwarranted. http://www.ivf.net/ivf/embryo-freezi...safe-o335.html However, since embryo freezing in humans is only as old as IVF- about 20+ years- we simply don't have life-long outcome data. But there have been tens of thousands, maybe hundreds of thousands of births using FET worldwide that don't demonstrate any obvious ill effects from starting life as a frozen embryo. If freezing is done poorly, the most likely effect is that too few embryonic cells survive the process and the embryo dies or is too damaged to implant or grow to it's full potential and the pregnancy fails before it ever gets started. With vitrification, damage from freezing is much much less common. The power of vitrification-done correctly- is that usually, post-warming, the embryo looks as good as before freezing. With traditional methods, we expected up to 50% cell death as "normal". IMO, FET, especially with vitrification is safe and effective. Carole

[bows&ribbons]

That article sounds a little scary. Seems like the embryos goes through so much stress to be frozen and then to be thawed! that is why i'd rather try fresh and freeze what i can for future transfer if the fresh doesnt take. We just dont know what the long term ramifications of this is...biopsying the embryo in of and itself is already complicating the already complicated iVF process.

[Carole]

Once you leave sex behind and enter the world of IVF, you have only about 30 years of human experience to draw upon. Ironically, freezing technology is what we have the most experience with because we have been freezing sperm and then embryos in the animal industry for decades longer than we have been doing IVF. I have the least concern that we will discover long-term problems from FET than from anything else we do.

Somewhere in this thread, you asked about biopsy and stage of embryo. Biopsy can be performed on the embryo on either day 3 or day 5. The morula stage embryo on day 4 is disorganized and it is not possible to recover a single cell cleanly and the trophectoderm layer is not developed at this day 4 stage so trophectoderm biopsy must wait for day 5 or day 6.

[bows&ribbons]

are there any articles discussing the safety of vitrification technology? The article you referred to me was written in 2004 and i am wondering if there have been any follow up studies. THanks!!
Also, the day 5 biopsy is done on what will become the placenta and other fetal membranes. Is there any way that these structures could be damaged and the embryo harmed in any way because of this biopsy? I believe Australia has been doing the day 5 biopsy for more time than we have -- have they had any negative experiences resulting fromt the day 5 biopsy e.g., more preterm labor, damaged placentas after babies are born etc? Thanks again for all of your help!

[Carole]

There are tons of articles in vitrification technology. You can simply google "embryo vitrification .gov" and find tons of articles to read. The ".gov" weeds out some of the weak opinion pieces. Some articles are written by IVF clinics, some are primary research articles. There is no shortage of articles to read about vitrification. Every year at the annual ASRM meeting, new evidence is accumulating to show that vitrification is an improved technology over slow freezing. If I were doing IVF to create a child, I would want my embryos to be vitrified and would only go to a lab that shows excellence with vitrification because IMO that demonstrates both technical proficiency and a commitment to improving outcomes for patients. Slow freezing is old technology that simply hasn't yielded the results possible with vitrification. Some researchers have shown better implantation for vitrified embryos than fresh embryos, probably because the uterus can be more receptive to implantation in a non-stimulated FET cycle. See a review of this here http://therotundaramblings.wordpress...er-ivf-babies/

Biopsy at any stage does not result in partial harm to embryos. IF the biopsy damages the embryo, it dies and implantation does not occur. There is no midway point with a organism of 10-100 cells where there is enough damage to cause partial damage but still allow implantation. Removal of a small number of cells for biopsy does not result in missing limbs in the fetus. Limbs won't develop until thousands of cell divisions later. The embryo on day 3 has less than a dozen cells, by day 5, it has about 100 cells. If you take a few cells away in the biopsy, especially when it is less than 10% of the cells, there are still plenty of cells left to get the job done. A loss of less than 10 cells at the earliest stage will not affect the function of the future placenta.

Best Wishes, Carole

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[bows&ribbons]

Does cryopreservation mean vitrification or slow freezing? how do i find out what type of freezing NYU practices? Thanks!

[Carole]

Dear bows&ribbons,
Cryopreservation is a general term that means preserving living cells by taking them to a temperature that is so low that metabolic processes don't take place and so the cells are in a state of suspended animation which is reversible. Under that umbrella term, there are two methods to get the cells to that ultra low temperature. Traditional slow freezing is one procedure to accomplish cryopreservation and vitrification is another procedure. Here's an eHow article I wrote that goes into more explanation http://www.ehow.com/how-does_5932899...rocedures.html. If NYU doesn't mention it on their website, you'll have to call their office and speak with someone in the lab. Hope this helps, Carole