I always say vitrification is the greatest discovery in the 21st century because it has allowed us to make the cycles more affordable. We’re going to have more embryo transfers if we have frozen embryos, with the slow freezing technique because of the survival rate, it was not possible.The embryos are stored in the tanks with nitrogen, they are kept well organized, and straws have different colours to identify them easier. Luis also presented 2 published papers that he took part in as well. One of them talks about the deleterious effect of estradiol hormone stimulation on embryonic implantation. The other describes 2 groups of patients, one with fresh embryo transfer and the other with warmed embryos. The paper showed that there are better results with wormed embryos, not because of the vitrification itself, but because of the first paper mentioned. It turns out that increasing levels of estradiol hormone stimulation can affect the implantation rate because it directly affects the embryo. Therefore, at Fertility Madrid, fresh embryo transfers are not performed, the embryos are vitrified and then transferred. ‘Vitrify all’ approach seems to be improving IVF outcomes.