Partial placenta previa?

I have had very light bright red spotting very seldom since my first trimester. Each time I've gone to the ER the baby is ok. First the doctors said I have a sensitive cervix and that if I have I would spot, but they didn't restrict me. I had no other spotting till a couple of weeks ago. This time they said I have a partial placenta previa, and that I need to be on pelvic rest. I haven't done anything ually since I was diagnosed. Today I discovered some bright red, but very light spotting. I don't want to be quick to run to the ER again for no reason. I'm just wondering if anyone knows if placenta previa can cause random spotting even without ual contact??