What level does the 8-day embryo cultured in vitro belong to? With the continuous development of assisted reproductive technology, in vitro fertilization has become one of the hopes for many infertile couples to achieve their reproductive dreams. The evaluation and selection of embryos is a crucial step in the process of in vitro fertilization. So what is the level of 8i embryos cultured in vitro for three days? To answer this question, we need to understand the relevant knowledge of embryonic development process and embryo scoring.

1、 Embryonic development process

After in vitro fertilization, the embryo undergoes a series of cell division and development processes. Under normal circumstances, the first division occurs around 24 hours after fertilization, forming a two cell two cell embryo. Next, the cells continue to divide, forming four cell embryos, eight cell embryos, and multicellular embryos. On the third day, the embryo usually develops to the embryonic stage of eight cells.

2、 Embryo score

Embryo scoring is the process of evaluating embryo quality and selecting the embryo with the most developmental potential. In embryo scoring, the main consideration is the appearance characteristics and cell development of the embryo. The appearance characteristics of an embryo include cell morphology and arrangement. The development of cells includes cell division speed and cell uniformity.

Embryo scoring is usually conducted using a grading or grading system, and different countries and laboratories may have different scoring standards. In China, the commonly used embryo scoring system evaluates based on the number of days of embryonic development and the number of cells. A typical embryo scoring system divides embryos into four levels, namely 4C, 4B, 4AB, and 4AA. Among them, numbers represent the number of days of embryonic development (calculated based on the number of days cultured to the eight cell stage), letters represent the uniformity of cell arrangement and the regularity of cell morphology, and A represents the best state.

3、 Rating of 8-day embryos cultured in vitro for three days

According to the embryo scoring system mentioned above, 8i embryos cultured in vitro for three days belong to the fourth level of embryos. Among them, the number 4 indicates that the embryo has developed to the eight cell stage (i.e. cultured until the third day), and the letter i indicates that the arrangement of embryonic cells is not uniform enough or the cell morphology is not organized enough. According to the standard grading system, embryos at this level may not be as high-quality as embryos at other levels.

However, it should be pointed out that the rating of an embryo only represents its basic quality and cannot fully predict its developmental potential and implantation ability. Sometimes, seemingly low-level embryos may also develop into healthy fetuses.

What level does the 8-day embryo cultured in vitro belong to? The 8i embryos cultured in vitro for three days belong to the fourth level of embryos. But embryo scoring is only a reference standard and cannot fully predict the developmental potential and implantation ability of embryos. Choosing which embryo to transfer also requires consideration of other factors such as patient age and egg quality. In addition, embryo scoring systems may also vary depending on the standards of different countries and laboratories. When choosing embryos for transplantation, it is recommended to consult a professional doctor to consider individual circumstances and actual needs. Through scientific evaluation and reasonable selection, the success rate of in vitro fertilization can be improved, helping more infertile couples achieve their reproductive dreams.