How to Make Sense of an Embryo Grading Chart: Step-by-Step Guide | AIVF
Understanding an embryo grading chart is just like understanding ancient Egyptian hieroglyphics. Both are almost impossible unless you’ve spent your whole life studying them. Embryo grading charts are tricky, especially as the grading system can vary between clinics.
Just as old scriptures contain valuable insights into centuries gone by, an embryo grading chart is an essential tool you and your clinic can use to feel confident in the decision to transfer the most viable embryos. The quality of embryos plays a big part in the success of your IVF journey, and the grading stage is when you can shed light on all this information.
What Is An Embryo Grading Chart?
An embryo grading chart is a visual tool that allows embryologists and fertility doctors to decide which embryos to use for embryo transfer. Traditionally, an embryo grading chart uses a score comprising numbers and letters (e.g., 5AA) or a rating (e.g., excellent, good, and poor). Embryologists examine each embryo to assess factors such as its structure, size, and cell development and give it a corresponding letter or number.
Clinics grade embryos at the cleavage stage (day 3 after fertilization) or the blastocyst stage (day 5 after fertilization). We’ll look at these two critical stages in more detail later in the article. It’s more common for embryologists to grade the embryos at the blastocyst stage (day 5) because their structure is more advanced, enabling more accurate grading. Sometimes, the clinic might think it’s best to grade the embryos after day 5 if they reach the blastocyst stage a little later.
After the embryos are graded, you can either proceed to a fresh transfer or freeze them for later use.
Why Does Embryo Grading Matter?
Although embryo grading doesn’t guarantee the final pregnancy outcome, it plays a significant role in maximizing your chances of IVF success. Research indicates that embryos graded as “excellent” have a 65% clinical pregnancy rate, compared to 33.3% for embryos graded as “poor.”
However, these facts and figures aren’t set in stone—even lower-graded embryos can one day become healthy babies. Embryo grading isn’t the only indicator of potential success rates. There are other factors at play, including:
- Hormones
- Medication
- Medical and ovulation history
- Age
- Diet and smoking habits
- Exercise history
Step-by-Step Guide to Reading an Embryo Grading Chart
Embryologists grade embryos on day 3 or day 5. Grading embryos on day 5 allows the embryologists to create a more detailed and precise embryo grading chart.
Embryo grading charts vary between clinics, so understanding them may sometimes seem confusing. If you’re concerned about anything you see on the chart or would like to discuss it, don’t hesitate to contact your fertility doctor.
Cleavage Stage Grading (Day 3)
On day 3, the embryos start cleaving (a fancy word for “dividing”), which means they divide but don’t grow in volume. Day 3 embryos still have the zona pellucida (another fancy word for the “outer shell”), which they break out of on day 5.
At the cleavage stage, embryologists grade embryos based on:
- Number of cells: Ideally, the embryo should be divided two or three times into six to 10 cells.
- Symmetry: High-quality embryos will have symmetrical cells.
- Fragmentation: A fragment is when small bits of the cytoplasm (the liquid inside the cell) break off. Higher-quality embryos generally have less fragmentation.
While embryo grading charts can differ between clinics, generally, cleavage-stage embryos are scored on a scale of one to five:
- 1 = excellent
- 2 = good
- 3 = average
- 4 = slightly below average
- 5 = below average
Blastocyst Stage Grading (Day 5)
By the time the embryos reach day 5 in their development and have passed through the morula stage, their structure has changed. Blastocyst-stage embryos fill with fluid, expand, and then hatch out of the zona pellucida. They will grow and eventually become different cell types, and they have:
- An inner cell mass called fetal cells.
- An outer cell mass (“trophectoderm”) called placental cells.
The embryo grading chart for day 5 embryos is much more complex and comprehensive, based on factors like:
- Blastocyst expansion: Embryologists are looking for embryos with a sizeable fluid-filled cavity (also called the “blastocyst cavity”). Some clinics use the analogy of a balloon filling up inside a ping-pong ball!
- Quality of inner cell mass (ICM): Higher quality embryos have tightly packed cells inside the inner cell mass.
- Quality of the trophectoderm: The cells in the outer trophectoderm (the outer layer) should ideally be evenly distributed and equally sized.
When the clinic grades blastocyst-stage embryos, the chart will look different compared to the grading for cleavage-stage embryos. As previously mentioned, the exact grading might vary depending on your clinic; many follow the Gardner scale for blastocyst embryo grading, consisting of a number followed by two letters (e.g., 5AA).
Here’s what the figures in the Gardner scale mean:
- A single number (1-6) = Rates the expansion and hatching stage of the blastocyst development.
- First letter (A-C) = The quality of the inner cell mass, as we explained above.
- The second letter (A-C) = the trophectoderm quality, also explained above.
Introducing a Simplified Way to Grade Embryos
Traditionally, embryologists review the embryos under a microscope to evaluate their developmental milestones. However, this traditional method has a few limitations, as human bias and subjectivity can influence embryo grading charts.
Embryo grading relies on each embryologist’s expertise and subjective opinion, but there’s no consistency and standardization in the IVF industry. As a result, embryologists sometimes face challenges in gaining visibility over in-depth grading analysis and predicting future outcomes.
Where New Technology Enhances Embryo Grading
New technology transforms how clinics score embryos, meaning giant, positive steps forward in IVF care and success rates. For example, AIVF uses a unique 0-99 viability scoring system powered by AI-driven algorithms.
AIVF enhances the embryo grading process by providing highly accurate and predictive assessments of each embryo’s potential (the quality and likelihood of success) to result in a successful pregnancy.
There are no Egyptian hieroglyphics to read, either—it’s a straightforward number from 0 to 99 representing the likelihood of euploidy (general normalcy, aka the probability of a healthy embryo). Based on this result, there is an AIVF score from 0-10, making it much simpler for you and your clinic to understand how healthy your embryos are and make decisions.
So, how does it work? Our embryo scoring system uses a proprietary AI model to analyze and score each embryo by identifying patterns and anomalies in time-lapse embryo images—factors impossible for embryologists to see.
The scoring is highly accurate, with no room for subjectivity or confusion. Research has shown that AI-assisted embryo grading systems can lead to a 30% increase in live birth rates compared to traditional grading methods. Accurate scoring means more peace of mind for you and a kinder IVF experience.
Highly Accurate Embryo Scoring Insights With AIVF
Sure, embryo grading charts can seem confusing if it’s unclear what you’re looking at or how to interpret the information. However, once you understand what the numbers and letters mean in real-life terms, you’ll feel totally confident and in control throughout this stage of your IVF journey.
At AIVF, we designed our cutting-edge EMA platform to ensure patients like you receive crystal clear and highly accurate embryo insights. The EMA platform gives you and your clinic enhanced transparency and insights throughout the decision-making stages, giving you peace of mind that you’re doing everything possible to maximize your chances of a successful pregnancy.
Clinics can use the AI-driven EMA platform to analyze embryos objectively, eliminating human biases and subjectivity and making way for non-invasive, precise screening coupled with a simple embryo score.
Find an AIVF clinic near you to take the first step in your journey.