As I’ve mentioned, we’re putting back two embryos this time. Decision is made. We’re not changing our minds. But there’s one little thing eating away at me. Let me explain.
Our baker’s dozen were frozen on day 4 as follows:
- straw #1: 2 perfect embryos
- straw #2: 2 perfect embryos
- straw #3: 1 perfect and 2 very good embryos
- straw #4: 3 very good embryos
- straw #5: 3 very good embryos
I believe the thaw survival rate is around 70%. Here are the possible scenarios:
Perfect scenario: thaw straw #1 and (fingers crossed) they both make it. Transfer two embryos.
Next best scenario: only one survives from straw #1, so we thaw straw #2. One also survives from straw #2. Transfer two embryos.
Least preferred scenario: only one survives from straw #1, so we thaw straw #2. Two survive from straw #2, giving us a total of three thawed embryos.
What do we do? Do we refreeze* the third? Do we just go ahead and transfer all three? Do we discard one? We really don’t want multiples (which is why we went with single ET last time) and transferring three would increase our odds of multiples. I think I’m leaning toward refreezing. But if my RE recommends against it, I don’t want the embryo discarded. Hmmm. What do you think?
*I found a little research (PDF) on refreezing embryos:
- Multi-cell embryos frozen once had a 76.3% survival rate after thaw and those frozen twice had a 74.0% survival rate.
- For frozen ET cycles that had no twice-frozen embryos, the viable pregnancy and implantation rates were 58.3% and 29.8%, respectively.
- The corresponding rates for cycles involving at least one twice-frozen embryo were 50.0% and 25.5%, respectively.