It is true that many IVF clinics still use the timing of the first cleavage or the number of cells on day 3 of development as the main criteria for selecting embryos for transfer. This approach has been used for many years and has been shown to have some predictive value for embryo viability.
However, recent advances in technology have allowed for more comprehensive evaluation of embryos, including the ability to culture embryos for up to 5 or 6 days (blastocyst stage), which can provide additional information on embryo development and quality.
Embryos that are cultured to the blastocyst stage can be evaluated based on criteria such as blastocyst morphology, inner cell mass (ICM) and trophectoderm (TE) quality, and degree of fragmentation. This can help identify embryos that are more likely to implant and result in a successful pregnancy.
Moreover, some studies have suggested that transferring blastocyst-stage embryos may result in higher pregnancy rates and lower rates of multiple pregnancies compared to transferring day 3 embryos.
Therefore, it is important for IVF clinics to consider the benefits of culturing embryos for longer periods and performing more comprehensive evaluations before selecting embryos for transfer. By doing so, they may be able to improve the chances of a successful pregnancy while minimizing the risk of complications.
Culturing embryos to the blastocyst stage allows for a more natural selection process to occur. In the human body, embryos do not implant in the uterus until they have reached the blastocyst stage. Therefore, culturing embryos to this stage can provide a more accurate assessment of which embryos are most likely to result in a successful pregnancy.
At the blastocyst stage, embryos have differentiated into two distinct cell types, the ICM and TE. The ICM is responsible for the development of the fetus, while the TE will eventually form the placenta. Evaluating the quality of these two cell types can provide valuable information on the embryo’s potential for implantation and pregnancy success.
Additionally, culturing embryos to the blastocyst stage can help identify embryos with a higher likelihood of implantation, allowing for the transfer of fewer embryos and reducing the risk of multiple pregnancies. Multiple pregnancies can increase the risk of complications such as premature birth, low birth weight, and other health problems for both the mother and the babies.
It’s important to note that culturing embryos to the blastocyst stage requires more time and resources, and not all embryos will reach this stage. However, advances in technology and culture media have improved the success rates of blastocyst culture and selection.
In conclusion, while evaluating embryos based on the number of cells on day 3 has been a standard practice in IVF for many years, culturing embryos to the blastocyst stage and evaluating their morphology, ICM, and TE quality can provide more accurate information on embryo viability and increase the chances of a successful pregnancy while reducing the risk of complications.
