Intracytoplasmic sperm injection (ICSI)

Intracytoplasmic sperm injection (ICSI) is an additional step to IVF. ICSI is the process by which a single sperm is injected into an egg. The fertilised egg is then placed into the uterus. This method may be recommended for couples who are experiencing fertility difficulties due to sperm-related infertility problems or if IVF has previously resulted in eggs not fertilising.

If you are having trouble naturally conceiving and you have been told that you (or your partner) have a low sperm count, you may be a good candidate for intracytoplasmic sperm injection (ICSI). To determine whether this fertility treatment is right for you, speak with your doctor about your options.

The ICSI Technique

Firstly, in ICSI, the egg and sperm are prepared separately. Then the egg is held in position by a pipette with gentle suction from a microinjector, with the polar body held away from the area to be injected. The embryologist then picks up the prepared sperm with a glass micropipette, pierces the shell of the egg and injects the sperm into the egg’s inner cytoplasm. The egg/sperm will then be placed in a culture medium, as normal, and checked the next day to see if it has fertilised. The egg and sperm are tiny and all this takes place using micromanipulators and a powerful microscope.

When to decide if ICSI is required?

Often the plan to use ICSI is made before the IVF cycle starts. A previous semen analysis will have identified the need for ICSI treatment. The final decision will almost always be reviewed by the embryologist when he or she sees the actual eggs and sperms on the day of the procedure. This sperm sample may be better than the semen analysis suggested, or it may be worse. Where possible we will always let nature take its course and let the sperms and eggs mix as naturally as possible without using ICSI.

The iTrust Fertility Clinics have an outstanding ICSI success rate

Our ICSI success rates are outstanding when compared to the national average. We advise that you read through our success rates pages and the HFEA website to get an idea of the different ways the statistics could be produced. Success rates vary according to age, health, and reason for infertility.

Our success rates are due to the expert care delivered by the team, ongoing monitoring and experienced healthcare professionals in fertility.

What is ICSI?

ICSI is a treatment used to treat patients with severe male factor infertility and for whom conventional IVF is inappropriate, has failed, or has produced very poor fertilisation previously. Its main advantage over routine IVF is that we only need one sperm to inject into each egg and therefore it is possible to achieve fertilisation in cases with severely reduced sperm counts, poor sperm motility, or low numbers of normally shaped sperm. It can also be used in cases where sperm has to be removed surgically from the testis, or when there are high numbers of anti-sperm antibodies present.

ICSI was first introduced into clinical treatment in 1992. It involves injecting a single sperm directly into the centre of each egg. The fertilized egg can then be transferred into the womb of the woman as in a normal IVF cycle. ICSI is simply an additional step to routine IVF, performed in the laboratory. Before and after the ICSI procedure, treatment is identical to IVF therefore please read the information about IVF.

Are all the eggs injected and does injecting cause any damage?

After egg collection, the eggs are prepared and assessed by the Embryologist. Only mature eggs will be suitable for injection, and not all the eggs collected will have reached the required maturity. Usually we will be able to inject at least 80% of the eggs collected.

The process of injecting the sperm does damage a small number of eggs (<10%). The damage usually becomes evident either during or after the procedure. Any eggs that are damaged in this way will not be used in the treatment.

How successful is ICSI?


Usually approximately 65% of eggs will fertilise regardless of the quality or numbers of sperm present. The chance of achieving a pregnancy with ICSI is very similar to that with conventional IVF.

Are there any other risks with ICSI?

Because ICSI is a fairly new treatment (it was introduced in 1992), it is not yet known whether there is any risk that injecting the sperm into an egg could damage it, with possible long-term consequences for the child.

  • Certain genetic and developmental defects in a very small number of children born using this treatment. However, problems that have been linked with ICSI may have been caused by the underlying infertility, rather than the technique itself.

  • The possibility that a boy conceived as a result of ICSI may inherit his father’s infertility. It is too early to know if this is the case, as the oldest boys born from ICSI are still in their early teens.

  • An increased risk of miscarriage because the technique uses sperm that would not otherwise have been able to fertilise an egg.

  • A low sperm count caused by genetic problems could be passed on to a male child, so you may want to undergo genetic tests before going ahead with ICSI.

  • Infertile men with low sperm count or no sperm in their ejaculate may be tested for cystic fibrosis genes and for chromosome abnormalities. You may want to discuss the full implications of taking these tests with your clinician or the centre’s counsellor before going ahead.