4BB on Day 6. :(

Milhetmama · August 14, 2026 at 7:10 PM New

Hi everyone,

I’m really at my wits’ end right now and would really appreciate hearing about your experiences. ❤️

I underwent egg donation in 2023. This resulted in a total of four blastocysts: one 5AA, one 4AA, one 2AB, and one 4BB.

Unfortunately, the first transfer with the 5AA didn’t work at all—it didn’t even implant. I was lucky with the transfer of the 4AA—that’s how my son was conceived. 🥰

Recently, the 2AB was transferred, but unfortunately, that attempt didn’t work either.

Now I only have the 4BB blastocyst left. The problem is: it didn’t develop into a blastocyst until Day 6. On Day 5, it wasn’t even certain whether it would be frozen at all.

My clinic says that they generally rank the embryos from “best” to “worst.” That’s why the 4BB was ranked behind the 2AB. However, if you go solely by blastocyst grading, a 4BB doesn’t actually seem any worse to me than a 2AB—after all, the expansion grade is 4, and both the inner cell mass and the trophectoderm are graded B.

Of course, I know that development on Day 5 or Day 6 plays a role. Still, the thought that my last chance is now a Day 6 4BB blastocyst really scares me.

So here’s my question for you:

Has anyone here gotten pregnant with a Day 6 blastocyst—maybe even a 4BB—and gone on to have a healthy baby? 🥰

I would really appreciate hearing about your positive experiences. Right now, I just need a little hope. ❤️

Conby · August 17, 2026 at 1:44 PM New

Hi Milhetmama, I’m hardly ever here anymore since our fertility journey has come to a happy end. But I’m happy to answer your question. I had two blastocysts from a donation. One was a 6AA, which actually didn’t develop into a blastocyst until day 6, and one was a 6BB, which was already a blastocyst on day 5. We had them tested via PGT-A, and both were healthy. A third, unhealthy one was discarded.

My first child was conceived from the 6AA blastocyst on day 6. My second child came from the Day 5 6BB blastocyst. Both are healthy. The classification is always just a snapshot, and it’s totally within the normal timeframe for a blastocyst to develop on Day 6. A score of 4, on the other hand, is pretty good. I’m keeping my fingers crossed for you. Best wishes,