The implantation rate per day five blastocyst transfer is greater than for transfer of day two or three embryos. However only 20% percent to 50% percent of day two embryos will develop in vitro to day five regardless of how good the in vitro culture system.
Whenever IVF or ICSI is performed, embryos may be cultured for either one day, two days, or maybe five days, before transferring them into the woman. in order to culture the embryos for five days, i.e. to what we call the “blastocyst” stage, you need to use “sequential” culture media systems. we have used such a system since the summer of 1997 because it offers us the choice of culturing the embryos for as long as is clinically applicable for each particular patient’s scenario.
However, there's a good deal of dialogue, and a few considerable commercial hype, cantering around whether or not to culture for two days, three days, or five or six days. The media we have a tendency to use, and which many other of the most effective programs use, permits us to culture the embryos to whatever number of days is acceptable for the actual patient. Since this media is usually available, it mustn't be used to hype any particular program.
For some patients with poor quality embryo development (a condition which is programmed into the genome of the many infertile women), even with the best culture media, the embryos could also be better off going directly into the fallopian tube immediately. For the average patient, day two or day three transfer either to the fallopian tube or to the uterus could also be best. for a few patients, day five transfer to the uterus could also be a good possibility. The problem with extended culture to day five is that there may be a loss of some embryos that might have “made it” if they had been transferred earlier.