Placenta Previa.

Placenta previa is an important and potentially life-threatening cause of bleeding. Historically, it was a major contributor to maternal mortality until advancements in obstetric care, including prenatal ultrasound, cesarean delivery, and transfusion medicine, drastically improved outcomes. Today, placenta previa is typically identified during routine second-trimester ultrasound, with the overwhelming majority of cases resolving before term. Key risk factors include prior cesarean delivery, advanced maternal age, and smoking. When placenta previa is diagnosed, it is essential to assess for associated conditions like placenta accreta and vasa previa. A planned cesarean delivery is recommended in cases that persist into the late third trimester.