ICSI (Intracytoplasmic Sperm Injection)

ICSI was developed in 1992 as a solution for severe male factor infertility. An embryologist uses a glass needle finer than a human hair to inject one sperm directly into the cytoplasm of a mature egg (MII oocyte). It overcomes barriers that prevent sperm from penetrating the egg on their own.

ICSI is used whenever sperm count, motility, or morphology is significantly impaired; when surgically retrieved sperm (TESA, PESA, TESE) are used; for frozen eggs; or after previous failed conventional fertilization. In many IVF programs, ICSI is now routine — even for couples without male factor — though evidence that it improves outcomes in unexplained infertility is limited.