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Birla Fertility & IVF
Birla Fertility & IVF

Embryo Grading and Success Rates: Everything You Need to Know

  • Published on November 02, 2023
Embryo Grading and Success Rates: Everything You Need to Know

Assisted reproductive technologies such as in vitro fertilisation (IVF) provide a ray of hope for infertile people and couples. When using in vitro fertilisation (IVF), the quality of the embryos is a major factor in predicting the success of the pregnancy. An essential part of this procedure is embryo grading, which offers important information about the viability and health of the embryos. We will go into the intriguing realm of embryo grading, its importance in the IVF process, and the variables affecting success rates in this extensive tutorial.

Understanding Embryo Grading

The process of evaluating an IVF-created embryo’s quality and developmental potential is known as embryo grading. When choosing which embryos to transfer into the uterus, this evaluation is a crucial stage. The grading procedure entails assessing multiple crucial facets of an embryo:

  • Number of Cells: An embryo’s cell count is a critical component. Usually beginning as a single cell, embryos divide as they expand in the early stages of development. The number of cells in the embryo is a measure of its development.
  • Symmetry of Cells: How uniformly the cells divide is another factor taken into account when evaluating embryos. The ideal shape and size of cells are symmetrical since this denotes appropriate development.
  • Diversification: The quality of the embryo may be impacted by cell fragments. It is best to have as little fragmentation as possible because too much fragmentation could point to a poorer embryo.
  • Blastomere Regularity: The regularity of blastomeres in an embryo is a crucial factor that determines its viability. Embryos that exhibit uneven patterns in this area are generally deemed less viable.
  • Cell Division Speed: Another crucial factor in grading is the embryo’s rate of cleavage or cell division. Generally speaking, healthier embryos divide at the predicted rate.
  • Nuclei Presence: The existence of a discernible nucleus in every cell is indicative of a healthy developmental stage.
  • Pelucida Zone: The thickness and transparency of an embryo’s zona pellucida, or outer layer, can also be evaluated.

Using these criteria as a guide, embryologists assess each embryo, usually on a five-point scale, where one represents the highest quality. An embryo in Grade 1 would, for instance, have a high cell count, good symmetry, and little fragmentation, whereas an embryo in Grade 5 would show considerable abnormalities and fragmentation.

Significance of Embryo Grading

In the framework of IVF, embryo grading fulfills a number of vital functions.

  • Selecting the Best Embryos for Transfer: How to Choose the Best Embryos Transfer: Finding the best-quality embryos that have the best chance of becoming pregnant is the main goal of embryo grading. Usually, these embryos are selected for uterine transfer.
  • Maximising the Prospects of Achievement: IVF facilities try to increase the odds of a successful pregnancy by transplanting the finest embryos. Better embryos have a higher chance of implanting in the uterus and growing into a healthy foetus.
  • Minimising the Chance of Several Pregnancies: The likelihood of multiple pregnancies, which are linked to increased medical risks for the mother and the unborn children, can be decreased by choosing the best embryos.
  • Reducing the Requirement for Extra Transfers: Patients may be able to become pregnant with fewer IVF rounds by transferring high-quality embryos, which would ease their financial and psychological burdens.

When making decisions about In vitro fertilisation (IVF), patients and experts can benefit from the useful tool known as embryo grading. It’s crucial to remember that while grades play a big role, they don’t determine success on their own. A successful pregnancy also depends on other factors like the woman’s age, the underlying cause of her infertility, and the environment inside her uterus.

Factors Influencing Embryo Grading

The following factors can affect embryo grading, which is not a precise science:

  • Age of Patient: One important consideration is the age of the lady supplying the eggs. Higher-quality eggs are typically produced by younger women, which may improve the quality of the embryos.
  • Protocol for Stimulation: The quantity and calibre of eggs extracted during IVF might be impacted by the ovarian stimulation procedure. Certain procedures could produce more embryos that are of inferior quality.
  • Laboratory Conditions: The tools, methods, and experience of the embryologists in the IVF laboratory can all affect the quality of the embryos. Top-notch IVF clinics make investments in cutting-edge infrastructure and highly qualified personnel to maximise the growth of embryos.
  • Hereditary Elements: Embromial quality can be impacted by genetic disorders. Certain embryos may be graded lower because of chromosomal or genetic problems.
  • Cryopreservation: After being frozen and thawed, embryos may undergo quality alterations that have an impact on how they are graded.
  • Individual Variability: The quality of embryos from the same IVF cycle could differ. For this reason, several embryos are frequently produced and assessed, providing possibilities for transfer to medical professionals.


Patients should be made aware that not all embryos will be of the best quality; this is a common occurrence. The important thing is to collaborate closely with your expert and other medical team to decide which course of action is appropriate for you given the embryos that are available and your unique circumstances. If you are looking for effective IVF treatment and seeking expert advice, schedule an appointment by filling out the form with the appropriate information. Or, you can call us at the number provided to fix an appointment. A medical coordinator will contact you as soon as possible to go over all the details.

Frequently Asked Questions (FAQs)

  • What is the Blastocyst Stage of Expansion?

The blastocyst can be evaluated and graded as a number ranging from the following characterisation:

Grade 1-Early Blastocyst

Grade 2- Blastocyst

Grade 3- Full Blastocyst

Grade 4- Expanded Blastocyst

Grade 5- Hatching Blastocyst

Grade 6- Hatched Blastocyst

  • What are pregnancy success rates by embryo grading?

It is said that the high-scored embryo may not have a successful chance of conception. However. several factors including embryo development and age can affect the pregnancy success rate by embryo grading.

  • How does day-wise embryo grading happen?

The following information is given day-wise to provide a better and clearer understanding of embryo grading:

Day 0 – Fertilization

Day 1 – Zygote

– 2 Cell Stage

Day 2 – 4 Cell Stage

Day 3 – 8 Cell Stage

  • Morula (16 Cell Stage)

Day 4 – Morula (32 Cell Stage)

Day 5 – Blastocyst

  • What is Inner Cell Mass (ICM) Quality in Embryo grading?

The inner cell mass is the group of cells that are present within the blastocyst that eventually form the fetus. The quality of inner cell mass is explained below according to the grades:

Grade A – Tightly packed, well defined, and multiple number of cells

Grade B– Loosely packed, less defined cells, and the number of cells in several

Grade C– Disorganized inner cell mass, very less or few cells in number

Written by:
Dr. Rashmika Gandhi

Dr. Rashmika Gandhi

Dr. Rashmika Gandhi, a renowned fertility specialist and laparoscopic surgeon, specializes in advanced treatments for infertility, endometriosis, and fibroids. Her expertise in 3D laparoscopic surgery, operative hysteroscopy, and innovative ovarian rejuvenation techniques, such as PRP and stem cell therapy, sets her apart. A committed advocate for high-risk obstetrics and preventative antenatal care, she's also a founding member of the Society for Ovarian Rejuvenation and a prolific academic contributor.
6+ Years of Experience
Gurgaon – Sector 14, Haryana

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