Intracytoplasmic sperm injection (ICSI) is another method of assisted fertilisation outside the woman’s body. It is generally used if the male partner’s fertility is significantly limited. There are several reasons for this: the semen contains either too few motile sperm (oligozoospermia, asthenozoospermia) or too high a proportion of malformed sperm (teratozoospermia). Or there is no sperm in the ejaculate (azoospermia) but a few isolated sperm have been retrieved from a testicular biopsy (a procedure called TESE).
With the ICSI method, individual sperm are introduced into mature egg cells via microinjection. The egg cell is fixed under a microscope and one isolated sperm cell is injected using a very fine pipette.
The advantage of ICSI is that even a very low number of fertile sperm is sufficient, while at least 50,000 to 100,000 healthy, motile sperm are required per egg cell for IVF.
Aside from this, all other steps are exactly the same as for IVF - even the success rates and risks are almost identical.