I'm going to try to answer both of your posts here so if I leave anything out, please let me know. IUI is a type of artificial insemination. It is getting the sperm all the way to the uterus to increase the chances of fertilization. Now I was very blessed and got pregnant on the first IUI attempt. However, I was told that there is about a 20% success rate for each try and on average it takes about 3 tries to get pregnant. I was 26 at the time, that was almost 2 years ago and I am looking at having it done again now. As for multiple births, I think your chances of them are much higher with in vitro than with artificial insemination. They do however give you fertility drugs to help you ovulate, so there is a higher chance of multiple births than with getting pregnant through sex, since you are increasing the number of eggs you have waiting to be fertilized is generally increased. Okay, hope that answers all your questions. Please let me know if there's anything I missed or anything else you would like to know.