If you have tried timed intercourse 3-4 cycles, it is now time to go ahead and do IUI. Many times though timing of intercourse is proper and ovulation happens we are not sure about the further stages that happen inside your body like the fertilisation, embryo formation and implantation. Obstacles can come at any if these stages. Also we cannot determine quality of eggs on sonography. So it is always good to have 2-3 eggs developing together so that at least one of them fertilises and a good embryo is formed. In an IUI cycle medicines can be given so that you develop more than 2 eggs. Further husband Semen sample is collected on the day of ovulation, processed in the lab and the sample is instilled inside the uterine cavity so that we put the sperms as close to the egg as possible and at the right time.