There are differences between this technique and classical in vitro fertilization. The steps before and after insemination are the same for classical in vitro fertilization without ICSI, only the technique used for insemination changes. In order to perform ICSI, only one sperm per ovule is needed, whereas in classical in vitro fertilization without ICSI, between 50,000 and 100,000 are necessary, since it is the sperm that has to overcome the ovule’s barriers to penetrate it. Once fertilized, the ovum becomes a pre-embryo and is transferred to the uterus so that it can continue its development.