# how to tell if blastocyst has survived defrosting?



## bettyb (Apr 13, 2005)

Hi
sorry if this sounds like a daft question but i was just wondering how to tell if a blastocyst has survived defrosting?
i was thinking that a day 3 embryo would continue to develop but how is it possible to tell if a day 5 embryo is ok
does anyone have any advice?
thanks
betty


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## ☼♥ Minxy ♥☼ © (Jan 13, 2005)

Hi

I'm obviously not an embryologist but I do know that not all clinics will thaw an embryo to see if it continues to grow overnight ie cleave/divide.

Our embies were thawed just before transfer as the actual thawing process doesn't take very long at all.  Ours were day 2 embies...first FET, 2 thawed and both survived 100% with no cell loss, in fact, one gained an extra cell between thaw and transfer...2nd FET, only 1 of the 2 thawed survived but it was still 100% in tact (those were 4 from our 1st IVF...we still have 6 from our 2nd IVF which were frozen on day 3)

As far as I'm aware, they can tell the embie has survived the thaw by looking at the overall quality of the cells...some may start to die off or it loses too many cells during thawing...some may also look "black" which means they've died...this is all because of the cooling process to freeze them, then thawing them and the ice shards can damage them. The same process would be used when checking how a blastocyst looks following thaw process.

Good luck
Natasha


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## Mustard (Aug 29, 2006)

Hi 

I'm not exactly sure how they tell either.  I have only had frozen blasts - in Jan I had 3 blasts thawed.  They did it on the morning of the booked ET, but unfortunately none survived the thaw  .  I now have 9 blasts frozen and will have be having a transfer on Friday - the clinic said they will only thaw 2 initially (as they're such good quality  ) and will see how they go and then keep thawing until they get 2 to put back.  They must be able to tell quite quickly I guess.  The consultant did tell me that the transfer won't be until the afternoon because they have to leave them for at least 4 hours after the thaw, so I guess they can tell in that time whether they're ok or not.

Good luck for your thaw  

Mustard
x


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