The best thing is just to be honest about what happened. I think they would be suspicious about a lie anyway.
Ok thank you I am waiting to tell them but I'm just trying to figure out ways while I wait
I found it hard to tell my parents the first time. My dad ended up being so excited he was going to be a grandpa. You just have to tell them, although I would suggest waiting till you start your second tri-mester. I lost my last baby at 10 weeks, right after I told my parents the news.
If your dad isn't as happy as mine was, you just have to tell him your happy and love your boyfriend. Once they see their grandbaby, I doubt they'll still have a problem