IUI (Intrauterine Insemination) is a fertility treatment where sperm are directly placed into the uterus to increase the chances of fertilization. It’s precisely timed with ovulation (using kits or trigger shots) and involves sperm washing to concentrate healthy sperm. IUI is suitable for couples with irregular cycles, healthy sperm/tubes, or unexplained infertility. Success depends on factors like age and sperm quality, with a slight risk of multiple pregnancies.