Human fertilization is a complex process. Out of millions of sperms deposited in the vagina during normal sexual intercourse only a few thousand sperms, reach the Fallopian tubes, the site of fertilization. This high loss is thought to be due to a various factors. Intrauterine insemination overcomes some of the barriers responsible for prevention of migration of sperms to the distal part of the Fallopian tube.
IUI is the direct placement of processed, highly motile, concentrated sperm, washed free of seminal plasma and other cells, into the uterus, adjacent to the medial ends of the Fallopian tubes, as close to the ovulated oocytes as possible.
