Intrauterine insemination (IUI) bypasses the cervix and places the sperm directly at the top of the uterus. From there sperm can reach the egg in the fallopian tubes within seconds.
IUI is often effective in treating mild male factor infertility since sperm are concentrated prior to placing them in the uterus. IUI is also effective in treating cervical factor infertility because the sperm are inserted through the cervix using a catheter, thus avoiding poor mucus and/or antibodies against sperm.
Learn more at the Center for Human Reproduction.