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

Egg/Sperm Freezing and Storage

Sperm can be frozen for future use either in artificial insemination or other fertility treatments, or be donated

Donated sperm has to be stored for six months before it can be used in treatment, in order to screen the donor for infections.

Sperm cells have been frozen and thawed successfully for more than 40 years.

Is sperm freezing and storage for me?

By storing your sperm, you may be able to use them for treatment in the future. You may want to discuss freezing your sperm with your GP or clinician if:

• You are facing medical treatment that may affect your fertility, for example, some forms of cancer treatment
• You are about to undergo a vasectomy
• You have a low sperm count or are producing sperm that are deteriorating in quality over time
• You have difficulty producing a sample on the day of fertility treatment
• Your sperm is going to be used for donation, in which case freezing allows the sperm to be quarantined for six months.