The grading of an embryo is determined by the embryologist at the time the embryo is frozen. It is a method used to evaluate the quality of the embryo. For helpful information about embryo development and quality, we recommend this article by Remembryo: Complete Guide to Embryo Grading and Success Rates
Donor Nexus partners with HRC Fertility, whose embryo grading is as follows:
• Fully Hatching Blastocyst (FHB), Hatching Blastocyst (HB) BB or better = A
• Expanding Blastocyst (XB) BB or AA = A-/B+ X
• Blastocyst (B) BB or AA = B/B-
• Early Blastocyst (EB) AA or BB = C+/C
• Compacting (Comp) = C-
To learn more, visit our Embryo Donation page.