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 fertilization.
In conventional IVF, the eggs and sperm are mixed together in a dish and the sperm fertilizes 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 fertilization, 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 fertilization will occur as the normal cellular events of fertilization 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 fertilization 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
- Fertilization of the eggs and culture of the embryos
- Transfer of the embryos back into the uterus.
- These steps are described more fully under IVF.
Facts about ICSI
The ICSI procedure is becoming more common in IVF clinics because it virtually guarantees that the sperm penetrates the egg. In 2010 over half of all IVF cycles performed in the U.S. used ICSI. And, the vast majority (87 percent) of couples dealing with male factor infertility used ICSI with their IVF cycles.
With the ability to fertilize an egg with just one sperm, many infertile couples are finally becoming pregnant. If you’re dealing with male factor infertility or other fertility problems, talk to your doctor about the ICSI procedure.