The primary symptom of placenta previa is sudden vaginal bleeding that is bright red and is not associated with any pain or tenderness of the abdomen, though in some cases it is accompanied by cramps. This bleeding tends to begin near the end of the second trimester or the beginning of the third. In some cases, the bleeding is severe; it can in some cases stop on its own, but start again a few days or weeks later. Labor can be accompanied by several days of heavy vaginal bleeding, and in some cases, bleeding may not occur until after labor begins.
If you have had these or other signs or symptoms of placenta previa, please consult your doctor.