The difference between fresh embryos and blastocysts usually mainly includes different culture time and different quality of embryos, etc. Embryo culture needs to be carried out under the guidance of professional doctors. Fresh embryos and blastocysts are two types of embryonic tissues that are developed differently during IVF due to the different culture time. Fresh embryo is an embryo in which the eggs and sperms have been cultured in vitro for three days; while blastocyst is an embryo that has been cultured for two more days than the fresh embryo, and the extra two days can effectively improve the quality of the embryo. Blastocysts have a higher implantation success rate than fresh embryos because they not only screen for embryos with better developmental potential, but also give the uterine lining enough time to prepare for implantation.