02/12/2021
📌Traditionally, embryo quality and development is assessed visually🧐: after fertilisation of the oocytes, the embryologist observes and classifies the embryos using a high-resolution microscope and a special contrast.
📌On the first day it is necessary to first assess the effectiveness of fertilization.
📌 On the second and third day of development the embryos will split - the subsequent cell division of the embryo.
📌The embryos that are transferred will be identified according to their quality: A-B-C-D, where A is the best quality embryo and D is an unsatisfactory embryo
📌 From day 4 onwards there is a change in the shape of the embryo in addition to the cell division: first the embryo compacts, the cell surface becomes smooth, this is the morula stage.
📌The blastocyst, an embryo ready for implantation into the uterine wall, is formed on day 5-6.
🧐The classification developed for the blastocyst is more complex than for the earlier embryos.
📌The selection of a quality embryo is a complex task, and the more advanced techniques and analysis tools are available to the embryologist in the clinic, the more likely it is that this selection will be the most accurate.
🧐More recently, embryologists have been able to monitor embryonic development almost continuously, thanks to new time-lapse microscopy technology.
🧐A special device is placed in the incubator where the embryos develop, which photographs the embryos at specific intervals and stores the images. As a result, the embryologist receives a kind of film 🎥about the development of each embryo.
📌If a couple is at risk of transmitting hereditary diseases, or if there is an increased risk of genetic anomalies during fertilisation and embryo development, not only the quality (external characteristics) of the embryos must be assessed, but also their genetic material must be analysed. In such cases, preimplantation genetic diagnosis (PGD) 🧬is performed in addition to visual assessment.
