pregnyl CAN delay AF, but doesn't always. it's a progesterone support, and it's the drop in progesterone at the end of the luteal phase that heralds the arrival of AF - so if you have support, it might prevent AF visiting. if you had IUI on day 17, and normally have a 14 day luteal phase, you'd expect AF on day 31 - so tomorrow - if you don't get it by Tuesday, you have a fair chance of getting good news. hope so! it's a fab feeling when i works out