Embryo Grading and Success Rates

Learning about embryo grading and success rates is a great place to start exploring your options when you have embryos created for IVF.

The quality of embryos created for in vitro fertilization (IVF) plays a significant role in predicting implantation and pregnancy success rates.

If you have embryos ready and want the best chances of pregnancy, you can find out if surrogacy is right for you and get matched with a surrogate in an average of 1 - 6 months. Learn more about available surrogates or get connected to a surrogacy professional now.

In this article, we’ll break down embryo grades and their relative success rates, discuss the impact of these grades on success, and explore how other factors influence outcomes.

IVF Embryo Grades and Success Rates

Embryo quality can be one of the biggest factors in IVF pregnancy success rates, which is why fertility medicine practitioners use grading scales to compare the quality of embryos.

Embryo grading typically utilizes either a letter system (A, B, C) or a numerical system (e.g., 4AA, 5AB). Embryo grades of A tend to be the best, with B and C grades being lower-quality.

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.

Because higher graded embryos usually have a higher likelihood of successful pregnancy, your medical provider will likely recommend that you use the highest quality embryo possible.

Depending on when your embryos are graded, the grading may look a little bit different.

Day 3 Embryo Grading and Success Rates

Here’s an overview of different grades of embryo at day 3 and why they might receive the grade:

• Grade A or 1: No fragmentation, and symmetrical. These embryos have the highest implantation potential.
• Grade B or 2: Minor fragmentation, and are mostly symmetrical. They have a moderate chance of success.
• Grade C or 3: Moderate fragmentation, and are asymmetrical. Their likelihood of successful implantation is lower.
• Grade D or 4: Heavy fragmentation, asymmetrical.

Some embryos stop developing or develop more slowly after day 3, so some practitioners will recommend that you wait until day 5 to determine which embryos to use.

Day 5 Embryo Grading and Success Rates

On day 5, embryo grading looks a little bit different because when the embryo develops, different parts of the embryo form. Here’s what a day 5 embryo grade is comprised of:

• Number (1-6): Expansion and development, with 6 being the most advanced development.
• First letter:(A-C): Inner cell mass (ICM) quality, with A being the highest quality.
• Second letter (A-C): Trophectoderm (TE) quality, with A being the highest quality.

Here are some grades for embryos and why they might receive that grade:

• 5AA: Optimal quality, fully expanded blastocyst with a well-defined inner cell mass (ICM) and trophectoderm (TE). High chance of success.
• 5AB: Good quality, moderately expanded, with a healthy ICM and TE. Still a viable option for transfer.
• 5BB: Fair quality; it may have a lower chance of implantation but can still succeed.
• 5CC: Poor quality, with less favorable chances for implantation and pregnancy.

Can Embryo Grade Predict Success Rates?

Studies have shown that higher-grade embryos correlate with higher pregnancy rates, but success is not guaranteed.

For instance, while Grade A embryos can have significantly higher implantation rates, even high-quality embryos could still fail to implant due to other factors.

And by the same token, some lower-quality embryos may implant even if higher-graded embryos failed. There are other factors to consider when it comes to predict success as well.

Limitations of Embryo Grading in Predicting Success

While embryo grading provides valuable insights many factors can have an effect on whether an embryo becomes a pregnancy.

Some of these factors include:

• Age of the Egg and Sperm Donor: Younger donors typically have better-quality eggs and sperm, which increase embryo quality and implantation rates.
• Egg and Sperm Quality: Even high-grade embryos can fail if the eggs used are of low quality.
• Uterine Environment: The health and receptivity of the carrier’s uterus can significantly impact the success of implantation, regardless of embryo quality.

Tips for Intended Parents to Improve Chances of Success

Even if you have lower-grade embryos, there are several strategies you can adopt to improve your chances of a successful pregnancy: If you are trying to get pregnant, you can consider lifestyle changes like:

• Healthy Diet: Focus on a balanced diet rich in fruits, vegetables, and whole grains.
• Regular Exercise: Maintain a healthy weight through regular physical activity.
• Avoid Smoking and Alcohol: Both can adversely affect fertility and embryo health.

Surrogacy

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

Choosing the Right Clinic:

Research clinics with high success rates and positive reviews. Consider those that offer personalized treatment plans and advanced technologies.

Fertility clinics can help you create embryos and determine embryo grades, as well as helping you transfer embryos to the uterus. Learn more about fertility clinics here.

Genetic Testing (PGT-A):

Even high-grade embryos may not implant if they have chromosomal abnormalities.

For instance, Grade A embryos can still carry genetic issues that prevent successful implantation. PGT-A can help identify these abnormalities, allowing for better-informed decisions about which embryos to transfer.

Preimplantation Genetic Testing for Aneuploidy (PGT-A) can help identify chromosomal abnormalities in embryos. This process complements embryo grading by ensuring that only genetically normal embryos are transferred, potentially improving implantation rates.

Understanding embryo grading and its limitations means you can make the best decisions for your family.

If you have embryos ready but you are concerned about your likelihood of success, 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

What is the most successful embryo grade?

Generally, Grade A embryos (like 5AA) are considered the most successful, with higher implantation rates.

Is 4AA or 5AA better?

A 5AA embryo is usually considered better than a 4AA due to its more advanced developmental stage and quality.

What is the pregnancy rate based on embryo grading?

Pregnancy rates vary significantly based on grading, with Grade A embryos having success rates around 60-70%, while Grade B and C embryos have lower rates.

Does embryo grading matter?

Yes, embryo grading is important as it provides insight into the quality and potential success of implantation. However, it should be considered alongside other factors that influence outcomes.