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Intra-Cytoplasmic Sperm Injection (ICSI)

What is ICSI and how does it work?

ICSI is a type of IVF (In vitro fertilisation) treatment that involves drawing up a single sperm into a very fine glass needle and injecting it directly into the centre of the egg.

The fertilised egg (embryo) can then be transferred into the womb of the woman as in a normal IVF cycle. ICSI is a relatively new technique (introduced into clinical treatment for certain types of infertility in 1992), but has already helped many couples. The live birth rates for ICSI and conventional IVF are similar.

This method bypasses any natural barriers that may have been preventing fertilisation. For example, some cases of infertility are due to the sperm of a male partner not being able to penetrate the outer part of the egg to fertilise the egg.

The major development of ICSI means that as long as some sperm can be obtained (even in very low numbers), fertilisation is possible.


Is ICSI for me?

ICSI is often recommended if:

  • The male partner has a very low sperm count.
  • Other problems with the sperm have been identified, such as poor morphology (abnormally shaped) and/or poor motility (poor swimmers).
  • At previous attempts at 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 (sperm reservoir).
  • Other situations where the sperm count is zero and donor insemination is not wanted.
  • The male partner does not ejaculate any sperm but sperm have been collected from the testicles.
  • The male partner has had problems obtaining an erection and ejaculating. This includes men with spinal cord injuries, diabetes and other disorders.
  • When there are high levels of antibodies in the semen.
  • When there have been previous fertilisation failures.

What does ICSI involve?

ICSI is similar to conventional IVF in that eggs and sperm are collected from each partner. To achieve fertilisation, a single sperm is taken up in a fine glass needle and is injected directly into an egg. The eggs are then incubated and examined. Usually one or two embryos may then be transferred back into the womb of the woman two or three days after fertilisation. Some eggs may not survive the injection process and not all eggs collected will be of a high enough quality or mature enough to be suitable for injection.


What are the risks of ICSI?

Because ICSI is a relatively new treatment, 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.

The risks that have so far been associated with ICSI are:

  • 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 clinic's counsellor before going ahead.

Inheritance of cystic fibrosis gene mutations

Some men who have no sperm in their semen are found to have congenital bilateral absence of the vas deferens (CBAVD). In this condition, the tubes that carry sperm from the testes to the penis are missing. Two thirds of men with CBAVD are also carriers of certain cystic fibrosis mutations. Men with CBAVD and their partners may therefore wish to undergo genetic testing before proceeding with ICSI. You can be referred to Genetics Department for more information and counselling about the implications of genetic testing.


Available leaflets:

Intra-Cytoplasmic Sperm Injection (ICSI)


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