ICSI (intra-cytoplasmic sperm injection) is an assisted conception technique, which may be, used where a male has only a few live sperm or where sperm quality is poor or lacking motility

It can overcome problems in which a sperm cannot drill a hole through the egg to fertilise it (for example, because of abnormalities affecting the sac of enzymes on the sperm head), and where anti-sperm antibodies are present. It can also be used where a male undergoing cancer treatment has previously frozen a sample of his sperm, and wants to maximise their potential use. ICSI has been used where there is a blockage preventing release of sperm, as the sperm can be obtained from the epididymis (the tube leading from a testis) or from the testis itself using a fine needle.

During ICSI, a single sperm is injected directly into the white (cytoplasm) of a mature egg using an ultra-fine glass needle (pipette). The fertilised egg is then observed until it has undergone a certain number of divisions before being transferred into the woman’s reproductive tract.

A fertilisation rate of 50 per cent is usual, with 80 per cent or more fertilised eggs starting to divide as normal. Factors such as the woman’s age (and therefore the age of her eggs) affect the success rate. The average live birth rate is 22 per cent, per embryo transfer, but the success of ICSI depends on the skill and experience of its practitioners