When it comes to fertility treatments, there isn’t enough awareness about the different types of treatments, add-on procedures, and investigative tests available to people who are experiencing fertility difficulties.
Being a private and sensitive issue for many, people tend to keep their doubts about fertility treatments to themselves, which can, sometimes, lead to a lack of understanding about the procedures they are undergoing.
Embryo grading is one such procedure.
While many people who are undergoing IVF treatment may hear about this procedure and ask themselves what embryo grading is, how it works, and how it can improve fertility, they may not be able to find the answers they’re looking for.
We believe that asking these questions and seeking information about fertility treatments is important in reducing the confusion, stress, and anxiety that comes with dealing with certain fertility issues.
That is why we strive to provide as much clarity as possible about this process.
What is embryo grading?
This is a procedure performed during the IVF treatment, where embryos are classified according to their potential for growth and development.
After eggs are collected from an individual and placed in a lab environment along with up to 50,000 sperm to increase the chances of fertilisation, a few eggs may develop into embryos.
At this point, they are graded based on their health and the potential for development.
How does it work?
All fertilised embryos are graded two times in their development cycle, three and five days after the egg retrieval process.
This allows embryologists to identify the best embryos to transfer or freeze in the transfer phase of an IVF cycle.
- Day-three grading
On day three, the embryos enter into what’s known as the cleavage stage—where the cells begin to divide, but the embryo itself doesn’t grow in size.
During this stage, embryologists grade the embryos based on the number of cells inside an embryo and the structure of these cells. Studies show that day-three embryos with more than eight cells have a higher live birth rate.
That said, embryos don’t always divide following a sequence and can sometimes have three, five, or six cells; the consensus is that the higher the number of cells inside an embryo, the more likely it is to improve fertility.
Many fertility clinics grade day-three embryos from 1 to 4—1 being the best quality and 4 being the lowest quality.
Grade-one embryos will have the most healthy cells and the least amount of fragmentation—the part of cells that break off during the cleaving process. Up to 20% of fragmentation is considered normal.
- Day-five grading
Day-five embryos are called a blastocyst, and during this stage, some of the cells form the Inner Cell Mass (ICM) that becomes the fetus. The remaining cells form the Trophectoderm Epithelium (TE), which develops into the placenta and other tissues that pregnant individuals require during the pregnancy.
During the blastocyst stage, the embryo expands inside the outer layer of the shell—the Zona Pellucida (ZP), which will become thinner to allow it to penetrate and implant in the uterus.
On day five, the blastocysts are graded based on three characteristics: how much they expanded inside the ZP, which is graded from 1 and 6, the quality of ICM, and the quality of the TE, which is graded from A to C.
Can embryo grading support your fertility journey?
The main purpose of this service is to choose the healthiest embryos for transfer, which, in theory, improves the chances of conceiving.
One thing to note is that although fertility clinics use several grading frameworks to rate embryos, all of these grading systems are subjective and may not always achieve the desired result.
There is a lot of debate about the effectiveness of embryo grading with regard to successful pregnancies, as there is conflicting evidence from multiple studies.
That said, for people seeking support and treatment to improve their chances, it is a potential opportunity to maximise their chances of conceiving and sustaining a healthy pregnancy.