Absolutely nothing to do with tattoos.
I was browsing the net, and I found that bellly rings are actually being made for pregnant women. They are much longer than the actuall belly ring, and they seem to be made out of a fiberous material that is flexible instead of metal. I am not sure as to how safe the actual stomach ring is. I would have to recommend to any woman who considers wearing one of these stomach rings to consult a doctor before buying one.