Intracytoplasmic sperm injection (ICSI) is a technique in which a single sperm is injected directly into an egg to increase the likelihood of fertilization.
Like other IVF procedures, the process starts with a mature egg which has been retrieved from the woman’s ovaries and prepared for in vitro fertilization. Sperm from the male partner (or donor) is retrieved either through normal ejaculation, or in the case of a vasectomy, a microsurgical vasectomy reversal is done. The mature egg is held in place with a glass pipette under a high-powered magnifying glass. At this point, a single sperm is selected and drawn through a hollow needle into a microscopic glass tube. The needle is then used to penetrate the shell of the egg and insert the individual sperm directly into the cytoplasm. The egg is then placed securely in an incubator and monitored over the next several days to verify that normal fertilization has occurred and the fertilized egg is developing into a healthy embryo.
ICSI is most useful in cases where an infertility diagnosis is related to low sperm counts, poor sperm motility or quality, or sperm that are unable to penetrate the egg. Besides being effective for male infertility, ICSI is also employed to fertilize frozen eggs.
Approximately half of all IVF procedures utilize ICSI. In couples with male-factor infertility ICSI can increase fertilization rates upwards of 70% to 80%. Some patients choose ICSI after first trying intrauterine inseminations (IUI) with unsuccessful results. ICSI is also used in cases when resulting embryos will be tested for chromosomal abnormalities, and gender (PGD).