What is Intracytoplasmic Sperm Injection (ICSI)?
The head of a sperm must attach to the outside of an egg before it can successfully fertilize the egg. Though many sperm are needed to activate this process, once attached just one sperm pushes through the outer egg layer to the inside of the egg (cytoplasm), where fertilization takes place.
In the case where the sperm cannot penetrate the outer layer, intracytoplasmic sperm injection (ICSI) a specialized technique to help fertilize the egg. During ICSI, a single sperm is injected directly into the cytoplasm (fluid center) of the egg. Though this procedure does not guarantee fertilization (creation of an embryo), it can increase the odds of fertilization in many cases.
When Is It Used?
ICSI can assist with overcoming fertility problems, such as:
- Insufficient number of sperm for intrauterine insemination (IUI) or traditional IVF.
- Sperm is not moving in a normal fashion (motility issues).
- Sperm has trouble attaching to an egg (morphology issues).
- Blockage in the male reproductive tract, such as an injury, varicocele, and absent vas deferens/cystic fibrosis that prevents sperm from being ejaculated.
- Prior vasectomy
- Previously frozen eggs are being used.
- Genetic testing of embryos (requires isolation of a single egg and sperm).
- Poor egg quality or few eggs (i.e., advanced maternal age).
What Do I Need to Know?
In the ICSI process, a tiny needle or laser is used to insert a single sperm into the center of an egg. With this technique, the egg and sperm have a better opportunity of combining their genetic information to result in an embryo. After fertilization, the embryo grows in a laboratory for up to 5-6 days, to the blastocyst stage during which time it may be transferred into the woman’s uterus (womb), biopsied for genetic testing, and/or frozen for future use.
Information Source: American Society for Reproductive Medicine