What symptoms do pregnant women with placenta previa experience?

Pregnant women with placenta previa typically experience vaginal bleeding. The most common symptom of placenta previa in early pregnancy is painless vaginal bleeding. If the bleeding is excessive, it may lead to transient unconsciousness and hemorrhagic shock, endangering the lives of both the mother and the fetus. In late pregnancy, as the cervical os dilates, the placenta shifts relative to the uterine wall and internal cervical os, causing blood vessels and sinuses within the placenta to bleed.