Some patients may not be able to benefit from intrauterine insemination (IUI) or conventional in vitro fertilization (IVF) due to inadequate numbers of motile sperm. (Motility refers to the ability of sperm to move actively.) In the past, the only alternative treatment for these couples was to use sperm for donors or to consider adoption.
However, in recent years, fertility specialists have perfected a procedure called intracytoplasmic sperm injection (ICSI). In ICSI, a laboratory specialist uses a tiny instrument and a microscope to directly inject a single sperm into an egg.
ICSI enhances the probability of achieving a genetically similar offspring even in the most difficult of male infertility cases.
When is ICSI the Best Option?
Moderate cases of male factor infertility may be successfully treated by conventional IVF treatment. However, ICSI offers an additional dimension of treatment for all more severe forms of male infertility.
ICSI may be the best choice when:
- Patients have low sperm density (less than 5 million), motility (less than 25 percent)
- Poor appearance (morphology) and/or sperm antibodies
- Cases with less than 50 percent fertilization or total fertilization failure in previous IVF attempts
- Patients have low or no measurable level of sperm azoospermia with sperm retrieved by sperm aspiration
How Does ICSI Work?
In intracytoplasmic sperm injection (ICSI), a laboratory specialist uses microscopic tools to isolate a single sperm and then injects it directly into an egg. This technique, used in conjunction with in vitro fertilization (IVF), has been especially successful as a treatment for men who have a low sperm count and women who have a small number of mature eggs.
In the IVF-ICSI procedure, the egg (oocyte) is prepared by removing its outer layer of cells called the cumulus. The oocyte is held gently by a holding pipette under a microscope.
The sperm that has been prepared for microinjection is then injected through a very fine micropipette into the body of the oocyte. The holding pipette is 20 times thinner than the human hair and the injection pipette is 60 times thinner than human hair.
The egg itself is no bigger than the tip of a pin. The microinjected egg is returned to the incubator and checked the following day for fertilization.
Men who have little or no sperm in their semen should consider genetic testing before ICSI. For men with extreme sperm abnormalities, up to 15 percent have some type of chromosome abnormality. Couples diagnosed with a chromosomal problem can seek genetic counseling to learn their potential for having a child with birth defects.