Intra-cytoplasmic sperm injection (ICSI) involves selecting and injecting a single sperm into an egg directly in order to fertilise it. The embryo is then cucltured for 2 to 5 days and then transferred to the woman's womb.

The major advance that ICSI offers to IVF, is that as long as some sperm can be obtained (even in very low sperm count numbers), fertilisation is possible.

ICSI can be recommended if:
• very low sperm count
• poor morphology (abnormally shaped) and/or poor motility
• previous attempts at in vitro fertilisation (IVF) there was either failure of fertilisation or an unexpectedly low fertilisation rate
• The male partner has had a vasectomy and sperm have been collected from the testicles or epididymis (TESE or MESA)