Understanding Embryo Grading and Success Rates for Pregnancy
If you’re an intended parent working with an egg donor or gestational surrogate, chances are you’ve heard the term “embryo grading chart” and wondered what it was and how fertility specialists use it.
Family Creations takes pride in working with all kinds of individuals and couples wanting to create a family. Because of our inclusive mission, we aim to be as transparent as possible about egg donation and surrogacy terms. In this article, we’ll give an overview of how embryo grading and success rates impact pregnancy. As always, contact us with any questions or concerns. Our staff is always available to help.
What Is an Embryo Grading Chart?
An embryo grading chart is a system doctors use to evaluate and classify embryos according to their physical attributes and development stage, particularly for use in in vitro fertilization (IVF) or other assisted reproductive technologies. The goal of embryo grading is to identify the embryos with the greatest potential to result in a successful pregnancy. This scientifically sound and trusted method has many years of research validation and is used by fertility doctors and clinics throughout the United States.
Embryo Grading and Success Rates
Embryo grades are typically given as a series of numbers, and higher grades are generally associated with better chances of achieving a pregnancy. The grades can give doctors valuable insights into the embryos’ potential for successful implantation and development into a healthy fetus.
What are the numbers and letters on an embryo grading chart?
While doctors will have advanced knowledge and training in fertility and embryo development, understanding the numbers on your chart is something anyone can learn. This knowledge helps you understand embryo grading and success rates for a viable pregnancy.
While most embryos are transferred on day 5 because the embryo is more robust and ready to be implanted, when only a few embryos are created or the embryos are low quality, a transfer may occur on day 3. Because day 3 embryos are more fragile, the uterus could provide a more natural environment to encourage the embryo’s further growth into a blastocyst (a cluster of dividing cells made by a fertilized egg).
Day 3 Embryos
Day 3 embryos are graded on a scale of A to D or 1 to 4, with A or 1 being the best quality and D or 4 being the lowest. These grades take into consideration the number of cells, cell uniformity, and fragmentation. A healthy day 3 embryo has six to 10 cells with uniform or evenly sized cells and little fragmentation.
Day 5 Embryos
Day 5 embryos are graded on a scale that commonly uses a number followed by two letters, such as 5AA or 4BB, on an embryo grading chart.
- The number refers to the embryo’s, or blastocyst’s, size and number of cells. 6 indicates the most highly developed blastocyst, which has hatched and completely emerged from the shell.
- The first letter on a scale of A to C on an embryo grading chart indicates inner cell mass quality. The inner cell mass will develop into the fetus. The letter A means that there are many tightly packed cells, while C indicates that there are very few cells.
- The second letter on a scale of A to C signifies trophectoderm quality. The trophectoderm forms the outer layer of the blastocyst and will develop into the placenta. Trophectoderm quality is also graded on a scale of A to C, with A indicating many cells that form a cohesive layer, while the letter C refers to a very few large cells that haven’t formed into a layer.
All information and notes are entered into the patient’s embryo grading chart for reference and record-keeping. Patients can view these records at any time.
Embryo Grading and Pregnancy Success Rates
A positive correlation, or likelihood, exists between an embryo’s grade and a pregnancy’s successful outcome. High-grade embryos typically have a higher potential for viability and a greater chance for successful IVF implantation, leading to a healthy pregnancy.
When considering embryo grading and success rates, the ideal day 3 embryos have a grade of 1 or A. At day 5, embryos that are rated between 3AA and 6AA are considered “excellent” and have the best chance of developing into a baby (about a 65%+ pregnancy rate and 50% live birth rate). “Poor” quality embryos may be of any number, but at least one of the letters will be a C if the number is higher than 2 (for example, 6BC, 4CB, or 2BB). Even these poor-quality embryos have around a 33% chance of leading to pregnancy.
It’s important to remember the following three points:
- Lower-graded embryos can still result in successful pregnancies, and a high-grade embryo is not guaranteed to be successful. The embryo grading chart is a tool that assists doctors in making the most informed choice.
- Embryo grading and success rates are based on physical observation and don’t indicate chromosomal abnormalities. Additional genetic testing is required to identify any genetic concerns. At Family Creations, all egg donors are required to undergo this testing before listing in our donor directory.
- Embryo grading is one of many factors that can influence IVF success. Others include age, health history, fertility issues, and even luck.
Important Points to Remember
For individuals or couples experiencing infertility, the journey to creating a family can often feel challenging. However, it’s important never to give up hope. Remember that the embryo grading chart is just one piece of the puzzle to creating a healthy baby. There can be well-graded embryos that don’t result in pregnancy and lower-graded ones that do. Embryo grading is a helpful tool for doctors but does not always precisely predict the success of an embryo implantation. This is why the grading system should be used in conjunction with other diagnostic tools to make a final decision.
Contact Family Creations for More Information
With over 15 years of experience working with intended parents, gestational surrogates, and egg donors, the professional staff at Family Creations has provided expert advice and compassionate direction to all seeking our family planning services. With offices throughout the United States, we are never far from you! Whether you are looking to start a family or help a family by serving as a surrogate or egg donor, we’d like to hear from you.