Last Friday, I emailed Carol, the embryologist at NEDC and found a few more things about the embryos we adopted.
Carol was able to tell us the quality of our embryos when they were cryopreserved. However, that does not mean that they will be the same quality when thawed and culture to transfer. The embryos will be re-graded after the thaw. We will be presented with pictures and their new grades at the time of transfer.
This was Carol's explanation of the embryos to me:
- For blastocysts (which is what we adopted), the embryos are normally graded with a number and two letters.
- The number is how expanded the embryo was at the time of cryopreservation and really does not have anything to do with the quality. Excellent embryos can be anywhere from 2-6, with a fully expanded embryo being a 5, and a hatched embryo being a 6.
- The first letter is the intercell mass which becomes the baby, and excellent quality are A & B, and then the letter goes down from there (C, D, etc.)
- The second letter is the trophectoderm which becomes the placenta and again A & B are excellent quality.
- From our first donor, the five embryos are graded at 3AA, 3AA, 3AA, 6AA and 4AA (all excellent quality embryos according to the embryologist). The embryos are frozen in three vials - 2 vials with 2 embryos each, and one vial with one embryo.
- From our second donor, all three embryos are graded at 4AA (again all excellent quality embryos according to the embryologist). The embryos are frozen individually, one embryo per straw.