Intra-Cytoplasmic Sperm Injection (ICSI)
Intracytoplasmic Sperm Injection (ICSI) is a specialized form of in-vitro fertilization (IVF) most often used for men who have poor sperm quality or low sperm counts. During an ICSI procedure, a single sperm is injected into each mature egg. ICSI has revolutionized the treatment of male infertility, and many thousands of children have been born worldwide as the result of ICSI treatment. Approximately 30% to 40% of all infertility is associated with a male factor. ICSI increases the chance of fertilization for men who have a very high proportion of abnormally shaped sperm (poor morphology), few moving sperm (poor motility) and very low sperm counts. Other indications for ICSI include;
- If the sperm that is to be used for fertilization has been cryo-preserved (frozen)
- If significant antisperm antibodies are present (antibodies produced by the man's body to his own sperm)
- Low or absent fertilization during past IVF treatment(s)
- If there is an obstruction in the male reproductive tract (such as following a vasectomy) and the sperm has to be obtained by an aspiration procedure
What does ICSI involve?
Eggs are retrieved from the female partner using the same technique as for standard IVF treatment (for more information please see our IVF webpage). Then the semen sample is prepared in the laboratory to isolate healthy moving sperm. Following egg retrieval, an embryologist (IVF scientist) examines the eggs under a microscope to determine which ones are mature and suitable for fertilization. The embryologist then carefully injects each of the selected eggs with a single sperm.
Following injection, the eggs are placed in an incubator, and the next day they are checked for signs of fertilization. An average of 70% to 80% of mature eggs will fertilize normally using ICSI.
What are the success rates?
Not all eggs fertilize, and not all fertilized eggs become good quality embryos. The best quality embryos (those most likely to develop into a healthy pregnancy) are selected for transfer and cryopreservation. Pregnancy rates are similar to those of standard IVF and vary with the age of the woman.
Tens of thousands of children have been born as a result of ICSI and approximately half of all IVF cycles performed in the world use ICSI.
Are there any concerns about ICSI?
One concern about ICSI is the possible health impact of this procedure on any resulting children. Some otherwise healthy men can carry a genetic cause for their low or abnormal sperm counts. These genetic abnormalities can be transmitted to a baby born through ICSI. The three most common known genetic abnormalities related to male infertility are:
- Cystic fibrosis gene mutations leading to congenital absence of the vas deferens (the tube that carries sperm from the testicle to the penis).
- Deletions of one or more genes present on the Y chromosome, called Y chromosome microdeletion.
- Chromosomal abnormalities, which may be associated with severely reduced sperm counts, or no sperm at all in the semen.
These abnormalities are associated with persistent and severe abnormalities on semen analysis. Because of this your Fertility Specialist may recommend one or more genetic tests before embarking on fertility treatment. Men who carry one or more of these chromosome problems may not be able to conceive a child, except using ICSI. If an abnormality is found, we may then refer you to a geneticist (medical specialist in human genetics) in order to be counselled about the implications and possible approached to future fertility care.
It is possible that children born after ICSI may inherit a chromosome problem or have a birth defect. From several large studies we know that the rate of chromosome problems and major birth defects is slightly increased (1% to 2% higher than the general population) in the offspring of men with low sperm counts, whether they conceive spontaneously or with ICSI.
A copy of our ICSI fact sheet can be found at the botom of this page.