Do I tell now or wait?

So I have been pretty open about our struggles with fertility with my mom who then tells my dad lol they know we are doing IUIs and that we had one earlier this month. Well surprise it worked!! My husband and I are thrilled but I'm struggling with whether I tell them now or wait until I've had bloodwork and an ultrasound. But then I would have to lie to them because my mom usually asks how things are going. We were pregnant once before 2 years ago and I told them right away! Well then my numbers weren't doubling, we had a blighted ovum and miscarried and my mom sat on the couch and cried with my because she is so excited to be a grandma. They are so supportive and always there for me but do I want to put them through that again if something goes wrong? So do I tell them now and hope for the best and know I have the support if something goes wrong. Or do I wait and tell them after we make sure numbers are doubling and have had an ultrasound. Thank you!