During your embryo adoption journey through Snowflakes, you might come across information about embryo quality and find yourself asking, "What do these letters and numbers mean?"
Rest assured, you are not alone! Terms like embryo quality and embryo grading can seem complicated, but we are here to simplify things.
What is Embryo Quality?
Embryo quality refers to a grade given by an embryologist or fertility specialist to assess how likely an embryo is to result in a successful pregnancy and healthy baby. Various factors are evaluated to assign this grade, but it is important to note that grading systems can vary across clinics, making things even more complex.
It is also worth mentioning that even if an embryo receives a lower grade, it can still grow into a healthy, beautiful baby!
Key Factors in Assessing Embryo Quality
- Morphology: This involves analyzing the embryo's physical characteristics under a microscope, such as cell number and symmetry. Ideal embryos have an even number of well-organized cells of similar size. Embryos that reach the blastocyst stage, typically by day 5 or 6 post-fertilization, are considered “higher quality.” At this stage, the embryo has a fluid-filled cavity and an inner cell mass.
- Genetics: Some embryos donated to Snowflakes have undergone genetic testing, known as preimplantation genetic testing (PGT), where a biopsy of the embryo is sent to a lab to check for chromosomal abnormalities. Embryos can be labeled as euploid (chromosomally normal), aneuploid (abnormal), or inconclusive if there was an issue with the sample.
- Developmental Timing: Specialists also monitor how the embryo progresses through its stages. Embryos that develop on schedule, particularly those that reach the blastocyst stage at the expected time, are generally considered higher quality.
Types of Embryo Grading
Different clinics use different grading systems, but one common system uses a scale from 1 to 6, with 6 representing the most advanced stage of development. The grading system also uses letters (A, B, C) to indicate quality, with A being the highest.
Grading Example:
Number – Refers to the expansion of the embryo's cavity:
- Grade 1: Early blastocyst (still developing, not fully expanded)
- Grade 2: Blastocyst
- Grade 3: Full blastocyst
- Grade 4: Expanded blastocyst
- Grade 5: Hatching blastocyst
- Grade 6: Hatched blastocyst (ready to attach to the uterine lining)
First Letter – Indicates the quality of the inner cell mass (ICM):
- Grade A: Many tightly packed cells
- Grade B: Loosely packed cells
- Grade C: Few cells, poorly formed
Second Letter – Describes the quality of the trophectoderm (TE), the outer layer of cells:
- Grade A: Many smooth, equally sized cells
- Grade B: Few to moderate large, healthy cells
- Grade C: Few large cells
Your healthcare team at our referral partner clinic locations will explain what the embryo grades mean for your specific situation through your embryo adoption journey.
Understanding the Limitations
It is essential to recognize that embryo grading is not an exact science. Variations between labs and specialists mean that grading can sometimes be inconsistent. While higher-quality embryos tend to be linked with better pregnancy outcomes, grading does not guarantee success. Lower-graded embryos can and do lead to healthy babies!
God created embryos to develop and form into babies, regardless of whether or not they are high quality or not! For more information about embryo adoption and donation, visit Snowflakes.org.