I have been diagnosed with partial placentia previa and I am 23 weeks pregnant, I had an ultrasound a month ago which found this and then had another one Friday which indicated it has not moved at all, I go back in another month to do yet another ultrasound to check its progress.
I was diagnosed with previa when I was pregnant two years ago but it moved by 18 weeks, my doctor said that after the 20 week mark it is less likely to move but not impossible.
I have read that with complete previa you are not likely to bleed until labor begins but with partial previa you can start bleeding at 28 weeks and premature labor, so is partial previa or complete previa more serious?

Try looking at this info on Baby Center (Placenta previa - BabyCenter)
I would say that your doctor is probably the best person to ask on this subject. Good luck to you hun, hope all works out well.

From what I understand, both are dangerous, but complete is worse. There is still a good chance that it will move. I was just talking with a friend of mine who HAD partial previa. They didn't catch it until later in her pregnancy. When she went in for her u/s to check it at 34 weeks it had finally moved. Obviously you will want to take it easy and watch for blood, but just know that all is not lost. It could still move, but if it doesn't you will be well taken care of by your doctor. Keep us updated on your progress!