Intra-cytoplasmic sperm injection (ICSI) involves injecting single sperm directly into an egg to fertilise it. The fertilised egg (embryo) is then transferred into the womb a few days later. The development of ICSI means fertilisation is possible even if there are problems with your partner's sperm and it is usually recommended if there is any reason to believe the egg will not fertilise with conventional IVF. Reasons for this may include your partner having a very low sperm count, or a very high percentage of abnormally shaped sperm, or a high level of anti-sperm antibodies. ICSI is also often recommended if less than 50% of eggs have been fertilised in previous cycles. Other than that, however, there is no
difference between ICSI and IVF in terms of the treatment you undergo.
The only difference is in the way the eggs are fertilised.
Fertilisation rates are slightly higher with ICSI compared to IVF (the average fertilisation per egg is about 60% to 70%, and more than 90% of women have at least one egg fertilised) as ICSI involves placing a sperm directly inside the egg. However, despite this, there is no significant difference in pregnancy rates. It is now used in approaching half of all IVF treatments in the UK.
On the day of egg collection the male partner will be asked to produce a semen sample which will then be prepared for insertion, in vitro, directly into one of your eggs. A second sample may be needed on the same day if the first sample is not suitable or sufficient. If your partner has very few sperm in his semen sample it is usually still possible to do ICSI. Even if he has no sperm at all then it is often possible to retrieve sperm surgically from the testicles or epididymis instead.
Basically, the development of ICSI has revolutionised male fertility, making it possible for men to have a family who would otherwise not have not been able to father their own genetic child.