“My friend has just miscarried. What should I say or do?”
Your friend is probably feeling very low and has to go to a grieving process. Sometimes you do not need to say anything, just by being there for your friend, it can go a long way for her.
Doing small things that can make a difference to her can say alot more than words. A hug also says a lot more than words.
The best thing I can tell you is just be there for her, and bear in mind that she will be grieving as to her losing a baby is just as real as losing a family member.