How do I help support someone after a miscarriage?

I believe my friend may have had a miscarriage and tomorrow she’ll find out. I haven’t mentioned to her that I think this is likely what happened and she thinks she is going to find out she is still pregnant. Miscarriage isn’t on her mind. I don’t feel comfortable sharing why I think this but it feels very obvious to me and other that this is what has happened. I don’t plan on bringing up my suspicions until she’s gone to the doctor to find out for sure what is happening. We’re young adults and I’ve never had anyone I know miscarry. If she finds out she did in fact miscarry, what is the best way to support her? Is there anything I should avoid talking about other than the obvious “you can still have kids in the future”? Is there anything specific that I should say to her? Thank you I’m advance.