What is Embryo Grading?

 Embryo grading can help your family have a better chance of successful pregnancy.

When sperm and eggs are combined in a medical facility for IVF, your fertility specialists can help you determine the health of each embryo. This process is usually completed on day 3 or day 5  of embryo development

This article will help with understanding embryo grading, so your family can make informed decisions about your options in surrogacy. 

Fertility clinics can help you create embryos and determine embryo grades. Learn more about fertility clinics here.

What is Embryo Grading? [Explained]

Embryo grading is a process that assesses the quality of embryos created for in vitro fertilization (IVF).

This evaluation helps predict the likelihood of successful implantation in the carrier’s uterus.

Embryos are usually graded on day 3 or day 5 because these days typically mark developmental milestones that help embryologists determine which embryos are best to transfer and when.

While embryo grading is an important factor, it’s essential to note that it is not the sole determinant of success; even lower-grade embryos can lead to successful pregnancies.

Embryo grading is one of several factors that affect success, including the age and health of the carrier.

How Does Embryo Grading Work?

Day 3 Embryo Grading (Cleavage)

At the Day 3 cleavage stage, embryos are typically assessed based on three criteria:

• Number of Cells Present: A healthy embryo at this stage generally has 6-10 cells.
• Degree of Fragmentation: Fragmentation refers to the presence of cell fragments within the embryo. Lower fragmentation rates are associated with better quality.
• Symmetry: A symmetrical embryo is often considered more viable than an asymmetrical one.

Day 5 Embryo Grading (Blastocyst)

At the day 5 blastocyst stage, embryos are graded based on three key components:

• Inner Cell Mass (ICM): This group of cells will eventually develop into the fetus. It is graded A to C.
• Trophectoderm (TE): This outer layer will form the placenta and is also graded A to C.
• Degree of Expansion: This measures how much the embryo has expanded, graded from 1 to 6.

Example grades: 5AA, 4AB, 5BC

How to Read Embryo Grading Scales

Understanding how to read embryo grading charts is crucial for families. Generally, A and B embryos are considered higher quality.

For example:

• A Day 3 Grade A embryo might look like this: 8 cells, low fragmentation, symmetrical.
• A Day 5 Grade 4AA embryo indicates excellent quality: a well-defined ICM and trophectoderm with good expansion.

It is important to note that each fertility clinic may use different variations of embryo grading, and fertility clinic success rates can vary.

Day 3 Embryo Grading Scale

Embryo grading scales usually range from grade A-D or 1-4 with A or 1 being the highest quality.

• Grade 1 or A:, No fragmentation, and symmetrical.
• Grade 2 or B: Minor fragmentation, and mostly symmetrical.
• Grade 3 or C:, Moderate fragmentation, and asymmetrical.
• Grade: 4 or D:  Asymmetrical with heavy fragmentation.

Day 5 Embryo Grading Scale

Expansion (1-6):

• 1: Early blastocyst, cavity just starting to form
• 2: Blastocyst, cavity is more defined
• 3: Full blastocyst, the cavity fills the entire embryo
• 4: Expanded blastocyst, larger and the outer shell is thinning
• 5: Hatching blastocyst, beginning to emerge from the shell (zona pellucida)
• 6: Fully hatched blastocyst, completely out of the shell

Inner Cell Mass (ICM) and Trophectoderm (A-C):

• Grade A: Clearly defined and well developed ICM and trophectoderm.
• Grade B: ICM and trophectoderm present.
• Grade C: Poorly defined ICM and trophectoderm.

Does Embryo Grading Matter for Surrogacy?

Yes, embryo grading plays a  role in assessing potential success rates for implantation. However, it’s important to recognize that while higher-grade embryos are often preferred for their higher rates of pregnancy, many low-grade embryos can still lead to successful pregnancies.

If you have low-graded embryos, surrogacy may increase your chances of successful pregnancy. Contact a surrogacy professional now or learn more about embryo grading and IVF.

How Accurate is Embryo Grading? [Success Rates]

In one study, AA embryos resulted in a 41% live birth rate, while BB embryos resulted in a 31% live birth rate and CC embryos were associated with a 13.1% live birth rate. But these statistics depend on several factors.

While higher-grade embryos (like 4AA) are statistically more likely to implant successfully, it’s essential to remember that:

• Lower grade embryos can also be viable options and may result in successful pregnancies.
• Factors such as the surrogate’s health and uterine environment also significantly impact outcomes.

If you have embryos ready, you can be matched with a surrogate in an average of 1 - 6 months. Learn more about available surrogates or get connected to a surrogacy professional now.

Frequently Asked Questions

Families who are interested in embryo grading commonly ask these questions:

Is a 4AA or 5AA embryo better?

A 5AA embryo is typically considered superior to a 4AA due to its more advanced developmental stage and quality indicators.

What is the most successful embryo grade?

Generally, Grade A embryos are viewed as the most successful due to their optimal cell structure and lower fragmentation rates.

What does embryo grading tell you?

Embryo grading indicates the potential for successful implantation and pregnancy but is not the only factor to consider.

Are grade B embryos good?

Yes, Grade B embryos are generally regarded as good quality and can lead to successful pregnancies, though they may have slightly lower success rates compared to Grade A embryos.

Understanding embryo grading can help families navigate the surrogacy process more confidently. By combining this knowledge with professional guidance, you can make informed decisions that align with their hopes and dreams for parenthood.