Blastocyst Culture
Blastocyst Culture
A blastocyst is the embryo at the 5th day of its development. It consists of significantly more cells (70–100) compared to embryos on the 3rd day (6–8 cells). These cells are divided into the inner cell mass (embryoblast), located inside the blastocyst, and the trophoblast, which forms the outer layer.
The embryoblast cells will later develop into the embryo within the uterus, while the trophoblast cells will form the placenta.
Blastocyst culture is a process in in vitro fertilisation during which embryos are allowed to develop in the laboratory until the 5th day. This approach allows the embryology team to select the embryos with the strongest developmental potential from those that initially began the process. Essentially, it is a method of selecting the best embryos and significantly improves pregnancy success rates in couples where it is applied.
Advantages:
- Selection of embryos with the strongest developmental potential in the laboratory.
- Higher pregnancy success rates. The endometrium appears to be more receptive on the 5th day after egg retrieval.
- Lower rates of multiple pregnancies when a single blastocyst is transferred, without reducing the chance of achieving pregnancy.
- Allows the performance of Preimplantation Genetic Diagnosis (PGD), which is carried out on the 3rd day embryos, while the healthy embryos are transferred to the uterus on the 5th day at the blastocyst stage.
- In some cases, blastocyst culture may help diagnose the cause of infertility in a couple. Although embryos may appear of good quality and develop normally until the 3rd day, they may later become moderate in quality or stop developing altogether.
Which couples is it recommended for?
Blastocyst culture and blastocyst embryo transfer are recommended when there is a large number of embryos from the beginning (at least 8), of which more than 4–5 have reached the 3rd day stage and continue developing with good prospects.
The couple should accept that some embryos may stop developing before reaching the blastocyst stage. As a result, in several cases there may be no embryos available for cryopreservation, while in rare situations no embryo may survive to the blastocyst stage for transfer.
