Intrauterine insemination (IUI) is an infertility treatment in which sperm are placed into your uterine cavity through a catheter. Intrauterine insemination (IUI) is a type of artificial insemination in which sperm are injected directly into your uterine cavity near the time you ovulate. Your doctor may recommend IUI to treat many causes of infertility, especially when there is a problem with the sperm such as low sperm count or low motility (when sperm do not move well). IUI bypasses the cervix, so it is a useful treatment if there is an incompatibility between sperm and the cervical mucus. IUI is