What’s involved in cultivating an embryo until the blastocyst stage?
The long-blastocyst culture consists of letting the embryos evolve in a medium under special conditions until their development to blastocyst on day +5 or day +6 (from the day of the transfer), being the most physiological form of transfer, since it is at this stage when the embryos would reach the uterus in a naturally produced gestation.
The blastocyst stage is the previous and necessary embryonic moment to be able to implant the embryo in the maternal uterus. The embryos that reach this development have already differentiated their cells, being able to find the cells of the Internal Cell Mass (MIC), which will give rise to the fetus and the cells of the trofectoderm (TF), which will give rise to the placenta.
What are the advantages of a day 5 or day 6 transfer?
To these advantages we must add that currently in embryology laboratories we have unique culture media of very high quality and Time-lapse incubation systems that offer culture conditions very similar to biological ones with the advantage of having built-in cameras that they allow us at all times to value the evolution of embryos.
When is the transfer done?
Blastocysts are generally transferred on day 5 after the follicular puncture, although it can be moved forward if not enough embryos will reach blastocysts ahead of time, or you may have to wait until day 6.
Each day following fertilisation the patient will be informed on the progress of the embryos and on day 5 she will be called and informed as to when the embryo transfer will take place.
Given that embryo development and reaching the ideal stage for transfer varies for each patient, even in different cycles, we are unable to know in advance when the transfer will take place. That’s why we recommend that you are attentive and wait for a call from the lab informing you of the procedure date.