Intracytoplasmic sperm injection (ICSI) is one of the most significant advances in reproductive technology in the last 25 years. Fertilization of the egg in the laboratory during in vitro fertilization (IVF) requires more sperm than one might imagine. Unfortunately, there are many instances in which sperm cannot fertilize the egg. ICSI is designed to help with this concern.
With ICSI, fertilization can be achieved with just a few sperm, so if any viable sperm cells can be found, ICSI is feasible. Furthermore, the sperm do not have to be normal. An abnormal, immature, or non-moving sperm can contain a normal complement of DNA — that is, if the genetic package is intact.
What is ICSI?
ICSI is a procedure that takes place during IVF. During conventional fertilization, a large number of actively moving sperm are mixed with an egg to fertilize “naturally.” If there are not a large number of sperm or enough normal appearing sperm, fertilization has a much lower chance of occuring. With ICSI, an embryologist injects a single sperm directly into the egg, significantly increasing the chance of eggs fertilizing and leading to the creation of healthy embryos.
When is ICSI Used?
ICSI is most commonly used in cases of severe male factor infertility. This includes:
- Low sperm concentration
- Poor sperm motility, or mobility
- Abnormal sperm morphology
Occasionally, ICSI is used in cases of low count or low quality eggs to maximize the chances of fertilization and implantation.
How is ICSI Done?
ICSI involves the use of specialized micro-manipulation equipment in the IVF laboratory. An egg is stabilized under the microscope with a special micro-pipette. A single sperm is then picked up into a second small needle-like pipette and injected directly into the egg. Sixteen to 20 hours later the egg can be evaluated and the presence or absence of fertilization noted.
What is the Effectiveness of ICSI?
Approximately 50-70 percent of eggs inseminated by ICSI will fertilize normally. ICSI, when necessary, helps to optimize the chance of pregnancy with IVF.
Does ICSI Have Risks?
One risk of this procedure is damage to the egg. Not all eggs undergoing ICSI will fertilize normally, and not all embryos that result from this procedure will develop normally. Thousands of children have been born as the result of IVF cycles in which the eggs were fertilized by ICSI. There is still some question about whether or not male infants born as a result of this procedure will have normal fertility.
This procedure is useful when there is severe male factor infertility, when there has been failure of fertilization in a prior IVF attempt, or if testing suggests a deficit in the fertilizing capacity of the sperm.
We also occasionally suggest TBS (“to be sure”) ICSI. While rarely encountered, defects in sperm fertilizing function can occur. TBS ICSI assures that such a defect will not result in complete failure of fertilization at the time of the initial IVF attempt. For couples in which the male has never fathered a pregnancy, doing ICSI on a few of the oocytes retrieved at the time of an initial IVF procedure helps to ensure that at least some of the oocytes will fertilize.