{"id":61826,"date":"2023-04-16T13:47:00","date_gmt":"2023-04-16T12:47:00","guid":{"rendered":"https:\/\/fertilityroad.com\/?p=61826"},"modified":"2024-09-23T20:53:41","modified_gmt":"2024-09-23T19:53:41","slug":"embryo-quality-guide","status":"publish","type":"post","link":"https:\/\/fertilityroad.com\/da\/ivf\/embryo-quality-guide\/","title":{"rendered":"Den gode, den onde og babyskaberen - Embryokvalitet - Klassificeringssystemer"},"content":{"rendered":"

Embryologists play a critical role in IVF clinics, we are the firts babysitters from day 0 (fertilization day) to day 6 of embryo development. We evaluate the embryos in culture first thing in the morning, observing them one by one and writing down all the relevant information. Each embryo requires its evaluation time and professional experience.<\/p>\n\n\n\n

The evaluation of the embryos is very important, since we will choose the embryos that are going to be transferred to the uterus and\/or frozen (vitrified).<\/p>\n\n\n\n

There are different classifications of embryos, depending on the day of culture and the regulations used for it, but all are based on the quality of the embryo, focusing on its characteristics. All classification systems work for embryologists to select the embryo with the best morphology.<\/p>\n\n\n\n

Understanding the quality of your embryo is very important. When you arrive at the clinic for an embryo transfer or receive a call from the embryologist explaining the quality of your embryos, it can sometimes be confusing to you, this is completely normal. For this reason, communication between the embryologist and the patient is very important at all times, to understand what the numbers and letters that your embryologist is explaining to you mean.<\/p>\n\n\n\n

The embryologist observes your embryos from beginning to end, they are in charge of taking care of the embryos day by day to choose the best candidate for a future baby. No one better than the embryologist can help you to understand the quality of your embryo.<\/p>\n\n\n\n

I accompany you to stay reading this article if you want to know more about the morphological quality of your embryos in a visual and professional way from an embryologist.<\/p>\n\n\n\n

Embryo quality – grading systems<\/strong><\/h2>\n\n\n\n

Each day of the development of the embryo is key to its development, with days 3 and 5 being the most important and main days in which patients receive updates. We will focus on days 3 and 5.<\/p>\n\n\n\n

Depending on the clinic an embryo grading<\/a> system is used, sometimes it is an internal classification, but all are based on the choice of the best embryo morphologically.<\/p>\n\n\n\n

Day 3 embryos have a classification based on the number of cells and their symmetry, the rate of embryonic division, the percentage and type of cell fragmentation, and other parameters such as the presence of multinucleation, vacuoles and the appearance of the pellucid zone. In some clinics the embryos are scored based on letters or numbers, with the number 10 and the letter A being the highest score, sometimes they are not even scored and only the information of the embryo is observed and noted. In our case we don\u2019t score embryos until day 5.<\/p>\n\n\n\n

Most clinics use the Gardner and Schoolcraft three-part scoring system for blastocysts on day 5 and 6, so we will focus on this since it\u2019s the one we use too. Let\u2019s learn it together.<\/p>\n\n\n\n

F\u00e5 mere at vide om IVF embryo development \u2013 insight into the Embryology Lab<\/a> – the voice from an experienced embryologist.<\/p>\n\n\n\n

Number: Blastocyst stages of expansion<\/strong><\/h2>\n\n\n\n\n\n\n\n\t\n\n\t\n\t\n\t\n\t\n\t\n\t
Grade of expansion<\/th>Name<\/th>Meaning<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>Early blastocyst<\/td>The blastocoel cavity represents less than half the volume of the embryo<\/td>\n<\/tr>\n
2<\/td>Early Blastocyst<\/td>The blastocoel cavity is more than half the volume of the embryo<\/td>\n<\/tr>\n
3<\/td>Full blastocyst<\/td>Cavity completely fills the embryo<\/td>\n<\/tr>\n
4<\/td>Expanded blastocyst<\/td>Cavity is larger than the embryo with thinning of the shell<\/td>\n<\/tr>\n
5<\/td>Hatching blastocyst<\/td>Hatching out of the shell<\/td>\n<\/tr>\n
6<\/td>Hatched blastocyst<\/td>Hatched out of the sell<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n\n

First letter: Grade of ICM<\/strong><\/h2>\n\n\n\n\n\n\n\n\t\n\n\t\n\t\n\t
Grade of ICM<\/th>Characteristics<\/th>\n<\/tr>\n<\/thead>\n
A<\/td>Many cells, thigtly packed<\/td>\n<\/tr>\n
B<\/td>Several cells, loosely grouped<\/td>\n<\/tr>\n
C<\/td>Very few cells<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n\n

Second letter: Grade of trophectoderm<\/strong><\/h2>\n\n\n\n\n\n\n\n\t\n\n\t\n\t\n\t
Grade of trophectoderm<\/th>Characteristics<\/th>\n<\/tr>\n<\/thead>\n
A<\/td>Many cells, forming a cohesive layer<\/td>\n<\/tr>\n
B<\/td>Few cells, forming a loose epithelium<\/td>\n<\/tr>\n
C<\/td>Very few large cells<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n\n

Embryo quality – cleavage (day 3)<\/strong><\/h2>\n\n\n\n

On day 3, embryos have between 6-10 cells it\u2019s a good indicator, the ideal would be to have an embryo with 8 even cells, since, according to studies, they are the ones with the greatest probability of reaching the blastocyst stage and with the highest live birth rate.<\/p>\n\n\n\n

As for the fragments, these are produced by abnormal cell divisions, a low level of fragmentation cannot interfere with the development of the embryo, but it is considered harmful when it is greater than 30%.<\/p>\n\n\n\n

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\"day-3-good-embryo\"
Embryo on day 3 with very good quality, 8 even cells and no fragments. <\/figcaption><\/figure><\/div><\/div>\n\n\n\n
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\"day-3-poor-quality-embryo\"
Embryo on day 3 with poor quality, uneven cells and fragments. <\/figcaption><\/figure><\/div><\/div>\n<\/div>\n\n\n\n
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Perfect development on day 3, an embryo with 8 even cells without fragments. The second picture shows us the compaction of these cells for the formation of the morula, the stage prior to the blastocyst (morula stage usually occurs on day 4 and can sometimes be day 3).<\/p>\n\n\n\n

Embryo quality – blastocyst stage (day 5)<\/strong><\/h2>\n\n\n\n

Day 5 is the most anticipated day since it is when embryo transfer and embryo freezing are usually carried out. Embryologists arrive at the clinic expectantly to observe the embryos and see the blastocysts grow.<\/p>\n\n\n\n

On day 5, embryos have between 64-128 cells. At this stage of growth, the embryo is referred to as a blastocyst. A blastocyst consists of two types of cells, the inner cell mass that will develop into fetal tissues, and the trophectoderm that will develop into the placenta.<\/p>\n\n\n\n

Based on Gardner and Schoolcraft three-part scoring system, we are going to see some of the most common examples that we see in the laboratory. This time, in a different way, from drawings of the embryologist’s eyes.<\/p>\n\n\n

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5AA. <\/strong>embryo top quality. This drawing shows a blastocyst beginning to hatch, with quality A of inner cell mass and trophectoderm. <\/figcaption><\/figure><\/div>\n\n\n

In the next section, we will see examples of the embryos that we can see in the laboratory on day 5 or 6, based on expanded blastocysts.<\/p>\n\n\n

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4AA<\/strong>. Number 4 indicates that the blastocyst is expanded, in this case an inner cell mass A, because it has many cells and they are compact, trophectoderm A with many cells and it form a cohesive layer. <\/figcaption><\/figure><\/div>\n\n\n
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4BB<\/strong>. Expanded blastocyst, the inner cell mass is present, but it is not very large, and the trophectoderm has few cells. <\/figcaption><\/figure><\/div><\/div>\n\n\n\n
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4CC<\/strong>. Expanded blastocyst with small inner cell mass with few cells, and very few cells in the trophectoderm. <\/figcaption><\/figure><\/div><\/div>\n<\/div>\n\n\n\n
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4AB. <\/strong>Expanded blastocyst with a very good inner cell mass, A. Trophectoderm with few cells, B. <\/figcaption><\/figure><\/div><\/div>\n\n\n\n
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4BA. <\/strong>Expanded blastocyst with an inner cell mass B, several cells, and trophectoderm A, with many cells. <\/figcaption><\/figure><\/div><\/div>\n<\/div>\n\n\n\n

Embryo quality and IVF success rates<\/strong><\/h2>\n\n\n\n

Embryo quality is a key factor in IVF success rates<\/strong>, but it’s important to remember that it is not the only consideration. While transferring high-quality embryos, such as a 5AA blastocyst, generally improves the chances of pregnancy, other factors also play a role:<\/p>\n\n\n\n