ICSI is recommended in cases of frozen oocytes that are thawed, due to the hardening of the zona pellucida (the cover or “shell” that surrounds the oocyte) when oocytes are frozen. “Standard insemination” for IVF (also known as “conventional” insemination for IVF) does not result in good fertilization rates in the case of frozen-thawed oocytes; however, ICSI is very effective in achieving fertilization since the sperm is injected into the oocyte’s cytoplasm, essentially bypassing the hardened zona pellucida of frozen-thawed oocytes.

Although the following are not absolute indications for ICSI, this procedure is commonly used commonly in cases of unexplained infertility as well as in cases of preimplantation genetic testing (PGT).

From the male factor standpoint, ICSI is recommended based on semen parameters.  When there is a low sperm count, very poor motility, or very few sperm with normal morphology (normal shapes), ICSI is recommended over traditional inseminated IVF.