IVF has helped thousands of people and couples realise their dreams of parenthood. During the IVF journey, your medical team may discuss ‘embryo grading, ’ but what does this mean, and what are your chances of success? This blog will explore embryo grading and why predicting the IVF outcome is essential.
What is Embryo Grading?
Embryo grading is a system that embryologists use to grade fertilized eggs (embryos). Embryologists look at factors such as the number of cells, rate of cell division, and overall cell structure after an egg has been fertilized and is dividing to determine quality. The quality of the embryo can be assessed on Day 3 (cleavage stage) or Day 5 and 6 (blastocyst stage). However, many clinics prefer blastocyst grading because it provides a more detailed picture of embryo development.
Common Grading Systems
The two most commonly referenced grading systems include:
Day 3 Grading (Cleavage Stage):
- Ideally, a Day 3 embryo has about 6–8 cells.
- Presence of cellular debris: This is known as fragmentation. Generally, the higher-quality embryos are those with minimal fragmentation.
- Grade: The better the grade, the more uniform and even the cells appear.
Blastocyst Grading (Day 5/6):
The most common system used is the Gardner Grading System, which considers:
- Expansion of the blastocyst (1–6): Determines how much of the cavity is expanded
- Quality of Inner Cell Mass (A–C): Group of cells that will form the fetus.
- A–C. Trophectoderm quality: The outer layer that will form the placenta.
For instance, a Day 5 embryo might be given the designation of 4AA: 4 (expansion level), A (inner cell mass grade), and A (trophectoderm grade). The closer to “A,” the higher the quality.
Why Does Embryo Grading Matter?
IVF success is an essential predictor of embryo grading. Embryos of high quality will have a higher chance of implanting in the uterus, resulting in a successful pregnancy. Yet, it is necessary to remember that grading is an assessment according to visual and structural criteria. A top-graded embryo does not guarantee implantation or pregnancy success, and a lower-graded embryo can still result in a healthy baby.
What Factors Influence Embryo Quality?
Factors that may affect embryo quality include:
- Genetic and chromosomal health of egg and sperm: Egg and sperm quality is key to embryo viability.
- Optimisation of embryo development: Proper culture environments and experienced embryologists.
- The mother’s health: A woman’s age affects egg quality, which can also affect the overall embryo quality.
- Reproductive health: Healthy lifestyle choices such as a good diet, minimizing stress, and avoiding harmful substances help improve reproductive health.
How Does Embryo Grading Affect Transfer Decisions?
Clinics choose the best embryos for transfer, which increases the chances of implantation. Preimplantation genetic testing (PGT) is a process where some patients have their embryos screened for chromosomal abnormalities. Genetic testing results and embryo grading add another layer of refinement to choosing which embryos to transfer, which may increase success rates.
Conclusion – Dr. Ram Prakash, Embryologist
Embryo grading is a key reference for fertility specialists, embryologists, and hopeful parents. It’s not an absolute predictor of IVF success, but it is one piece of the puzzle that helps inform decisions about embryo selection and transfer timing.
Embryologist Dr. Ram Prakash meticulously oversees every stage of the IVF process, from fertilization to embryo development, ensuring expert care and precision. Learning about embryo grading helps patients to feel more empowered and informed about decisions that they make, bringing them a step closer to the dream of starting a family.