IUI is often performed if a man’s semen quality is moderately impaired and there are too few sperm cells that are intact or have good motility. Specially prepared sperm cells are transferred directly into the uterus at ovulation. This is carried out using a fine tube (catheter). The advantage of this method is that the sperm’s journey to the egg cell is significantly shortened. As a result, the sperm cells reach their destination more quickly and in greater numbers, which increases the chance of fertilisation.