Intracytoplasmic sperm injection is an in vitro fertilization (IVF) procedure in which a single sperm cell is injected directly into the cytoplasm of an egg. This technique is used in order to prepare the gametes for the obtention of embryos that may be transferred to a maternal uterus. With this method acrosome reaction is skipped.
There are several differences within classic IVF and ICSI. However, the steps to be followed before and after insemination are the same. In terms of insemination, ICSI needs one only sperm cell per oocyte, meanwhile IVF needs between 50 and 100 thousands. This is due to the fact that in IVF acrosome reaction has to take place and thousands of sperm cells have to be involved. Once fertilized, the egg is transformed into a proembryo and it has to be transferred to the uterus to continue its development.