Q from U: Growth potential of frozen vs. fresh embryos
March 28, 2012Carole 2 Comments »Hi Victoria,
You asked me: Do previously cryopreserved embryos develop similarly to fresh embryos so that, if one is attempting an e-SET, growing them out is one way to determine the ‘best’ one or are they somehow more fragile?
How well thawed embryos grow out depend on several factors:
- method of freezing and thawing (Vitrification has the potential to completely preserve the integrity of the cells meaning no cells die, if performed properly compared to slow freeze protocols in which some loss of cell viability is expected)
- How well method was performed (Even vitrification, if done poorly, can kill some or all of the cells)
- Both the freezing and the thawing (thawing is termed “warming” for vit) must be done expertly. A botched freeze can’t be saved by a perfect thaw and vice versa.
- The culture method employed by the clinic (can they routinely grow fresh embryos to blastocyst stage- or is this problematic for them?- do they mostly transfer on day 3?), If day 5 culture is one of their strengths, go with it.
- Intrinsic properties of the embryo (genetic or metabolic) which determine if it will continue or die
If all these factors are in your favor, it is perfectly reasonable to grow thawed embryos out in culture to see which ones can make it to blastocyst stage because these are most likely to implant. Frozen embryos shouldn’t really be more fragile once they have recovered from the freeze/thaw process. The only other alternative is to thaw one for eSET and hope for the best (that it will progress appropriately and be transferred) which is more risky than thawing several and growing them out to select for one “best”. Good luck for a positive pregnancy!!
Related posts:
Embryo stages, progression and pregnancy outcomes
© 2012, Carole. All rights reserved.
April 9th, 2012 at 6:40 pm
I so appreciate this as I am nearing transfer with donated embryos set for this weekend. We have three, vitrified in one straw, that we will thaw on Friday. With our previous FET we planned for an e-SET and with one compacted morula thriving from the three that is what we got. This time, we will transfer all that are growing.
Fingers crossed for success at this last effort.
April 9th, 2012 at 6:42 pm
Wishing you Much Good Luck!!! Carole