Intracytoplasmic Sperm Injection (ICSI) is a technique sometimes used with in vitro fertilisation (IVF) in which one sperm is injected directly into one egg in order to fertilise it. This is especially useful for men with very low sperm counts since ICSI ensures that the sperm reaches the egg directly rather than waiting for the sperm to naturally fertilise the egg.

Who should be treated with intracytoplasmic sperm injection?
In vitro fertilization (IVF) with ICSI is recommended for:

1. All couples with severe male factor infertility that do not want donor sperm insemination.
2. All couples with infertility with:
   • Sperm concentrations of less than 15-20 million per milliliter
   • Sperm motility less than 35%
   • Very poor sperm morphology (subjective - specific cutoff value is not appropriate)
3. All couples having IVF who have had a previous cycle with no fertilization - or a low rate of fertilization.
4. All couples having IVF who have a very low yield of eggs at the egg retrieval - our current cutoff is 5-6 (or less) eggs. In this scenario, ICSI is being used to try to get a higher percentage of eggs fertilized than with conventional insemination of the eggs (just mixing eggs and sperm together).

How is ICSI performed?

The process starts with preparation for this procedure. The woman is given fertility drugs to stimulate egg follicle development and ovulation. Her mature ova are then retrieved to use during ICSI.
In additional preparation for ICSI, sperm is collected from the man. In cases where it is possible, sperm can be collected from a semen sample. An alternate option is to harvest the sperm directly from the man's testicles using a testicular biopsy under anesthetic.
The single sperm is then injected directly into the woman's harvested egg with a very delicate needle. The egg will reseal itself after the needle is withdrawn, just as it does in the process of natural fertilisation when the sperm breaks through its outer membrane.
As in in vitro fertilisation(IVF) without ICSI, the fertilised egg is then allowed to develop for a few days before being transferred back into the woman's uterus in the form of an embryo.

Figure 1:
Immobilizing the sperm's tail before picking it up.

Figure 2:
Injection of sperm into the egg.

Figure 3:
Fertilized egg demonstrating the two nuclei – one from the father, one from the mother.

The successful rate of ICSI:
ICSI is currently the most successful treatment for male infertility, with fertilisation rates of 60%-70% depending on quality of the sperm used.
However, once the egg is fertilised, the success rates of ICSI in conjunction with IVF remain the same as conventional IVF – a 20%-25% chance of live birth. This is because overall effectiveness still depends on the fertilised egg developing properly in addition to successful implantation into the uterus.
In some cases, assisted hatching may be used to increase the chances of implantation.

The risks of ICSI:
One concern about ICSI is the possible health impact of this procedure on any resulting children.Because it is possible that a weaker, poorer quality sperm might be used in ICSI, congenital defects may be passed on at a higher rate than naturally or with other methods of IVF.

Also, because ICSI is a relatively new procedure, the long-term effects for resulting children have yet to be properly analyzed.
Couples who want to conceive using ICSI are still advised to analyze their family history for genetic diseases and disorders and consult with a doctor. They may also want to consider pre-implantation genetic diagnosis (PGD). Finally, because ICSI is used in conjunction with IVF, the risks of IVF apply here too; namely, increased chances of ectopic pregnancy and multiple births.