The biggest challenge in IVF success is to select the best embryo for transfer which will develop as a normal pregnancy. Most common reason for embryos not implanting is a genetic abnormality in the embryos.
There are very good monitoring parameters to judge which embryo is better. That includes egg quality, embryo development speed, embryo quality etc. However, better techniques are required.
Culturing the embryos in IVF lab till blastocyst stage – blastocyst culture, Preimplantation genetic testing – PGS- PGT – A, are the two best options. Blastocyst culture has many advantages over PGS. It is non-invasive on embryos, simpler to do, much less expensive also. The limitation is that it does not tell about the actual genetic constitution of the embryos.
When an embryo becomes 5 to 6 days old, it reaches a stage of development which is called “ BLASTOCYST ”. In natural conception, the sperm fertilizes the egg in the fallopian tube. The embryo grows in the fallopian tube and slowly moves towards the uterus. An embryo reaches the uterus – endometrium after 4 to 6 days of fertilization at the blastocyst stage.
All embryos which look good on day 2 or 3 of development may not develop further. If we culture them for more days, only the good quality embryos of them may develop further and reach the blastocyst stage successfully. The remaining stop developing at various stages in between. It is impossible to know which embryos will reach the blastocyst stage.
We can select and transfer one or two blastocysts and still achieve a very good pregnancy rate. This is called Blastocyst Culture.