What is IUI – Intra-Uterine Insemination? Intra-Uterine Insemination involves the injection of a small amount of prepared concentrated sperm from the partner into the woman’s uterine cavity via the cervix. Success rates are about 10-15% per cycle and depend on age, the quality of the sperm or whether ovulation drugs are used. IUI is recommended for women with explained sub-fertility and tubal patency has been confirmed, and the sperm preparation is satisfactory. The procedure only takes a few minutes, and is performed on an outpatient basis. It is relatively easy and pain free. Ultrasound scan is used to monitor the response to the drugs and to time ovulation. The insemination is timed to take place 24-40 hours after administration of the hormone injection hCG, which triggers ovulation. On the day of IUI, the male partner is asked to produce a semen sample 1-2 hours before insemination. This sample is examined and prepared in the laboratory, and is then inseminated into the uterine cavity by using a fine IUI catheter.