Intracytoplasmic Sperm Injection (ICSI)

Intracytoplasmic Sperm Injection (ICSI)

What is ICSI?
Who is ICSI suitable for?
What does ICSI involve?
How Successful Is ICSI?


Diagram illustrating the process of intracytoplasmic sperm injection (ICSI)

Figure 1. Diagram illustrating the process of intracytoplasmic sperm injection (ICSI). The egg is held in place while a single sperm is injected into the cytoplasm of the egg using a very fine needle.

What is ICSI?

ICSI is very similar to conventional IVF in that gametes (eggs and sperm) are collected from each partner. The difference between the two procedures is the method of achieving fertilisation.

In conventional IVF, the eggs and sperm are mixed together in a dish and the sperm fertilises the egg ‘naturally’. However to have a chance that this will occur, large numbers of actively swimming normal sperm are required. For many couples, the number of suitable sperm available may be very limited or there may be other factors preventing fertilisation, so conventional IVF is not an option. ICSI has provided a hope for these couples.

ICSI refers to the laboratory procedure where a single sperm is picked up with a fine glass needle and is injected directly into each egg (Figure **). This is carried out in the laboratory by experienced embryologists using specialist equipment. Very few sperm are required and the ability of the sperm to penetrate the egg is no longer important as this has been assisted by the ICSI technique. ICSI does not guarantee that fertilisation will occur as the normal cellular events of fertilisation still need to occur once the sperm has been placed in the egg.

Who is ICSI suitable for?

From a patient perspective, undergoing an ICSI treatment cycle is exactly the same as a conventional IVF cycle, and the same steps are involved.

Circumstances in which ICSI may be appropriate include:

  • When the sperm count is very low
  • When the sperm cannot move properly or are in other ways abnormal
  • When sperm has been retrieved surgically from the epididymis (MESA/PESA) or the testes
  • (TESE/TESA), from urine or following electro-ejaculation
  • When there are high levels of antibodies in the semen
  • When there has been a previous fertilisation failure using conventional IVF.

What does ICSI involve?

From a patient perspective, undergoing an ICSI treatment cycle is exactly the same as a conventional IVF cycle. Patients should however be aware of the risks associated with ICSI.

  • Stimulation of the ovaries to encourage development and maturation of the eggs
  • Retrieval of the eggs
  • Fertilisation of the eggs and culture of the embryos
  • Transfer of the embryos back into the uterus.
  • These steps are described more fully under IVF.

How Successful is ICSI?

Chances of success vary between patients, particularly according to the age of the woman, but on average about 25% of patients will have a baby after one attempt at ICSI. Recent results for ICSI at our clinic are shown here.

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