Intracytoplasmic Sperm Injection (ICSI)
Definition - What does Intracytoplasmic Sperm Injection (ICSI) mean?
Intracytoplasmic sperm injection (ICSI) is a method of fertilization where a single sperm is injected directly into an egg as part of an in vitro fertilization procedure.
The procedure involves the extraction of an egg (through ovarian stimulation and egg retrieval) that is then manually fertilized in a lab with a single motile and morphologically normal sperm that is inserted into the cytoplasm of an egg with a hollow needle.
Any resulting embryos can then either be transferred into the recipient's uterus or frozen for a transfer at a later date. Very few sperm are required for this process, making conception possible even with severe male infertility issues.
FertilitySmarts explains Intracytoplasmic Sperm Injection (ICSI)
ICSI is most frequently used to address male infertility factors that impact the quality or volume of sperm or the ability of sperm to penetrate an egg. These include:
- A low sperm count
- When sperm have abnormal morphology (size and shape)
- When sperm have limited motility (movement)
- When sperm are surgically removed from the epididymis (MESE) or testicles (MicroTESE)
- When there are high levels of antibodies in the semen
- When there is a high level of sperm DNA fragmentation
- When working with a low yield of eggs retrieved to maximize the potential number of fertilized eggs
- When previous eggs extracted for IVF failed to fertilize using conventional insemination when sperm and egg are mixed together externally
Intracytoplasmic morphological sperm injection (IMSI) is a modification of ICSI that allows an embryologist to better assess sperm morphology.