Abstract Objective To review the use of transvaginal ultrasound for the diagnosis of placenta previa and recommend management based on accurate placental localization. Options Transvaginal sonography (TVS) versus transabdominal sonography for the diagnosis of placenta previa; route of delivery, based on placenta edge to internal cervical os distance; in-patient versus out-patient antenatal care; cerclage to prevent bleeding; regional versus general anaesthesia; prenatal diagnosis of placenta accreta. Outcome Proven clinical benefit in the use of TVS for diagnosing and planning management of placenta previa. Evidence MEDLINE search for “placenta previa” and bibliographic review. Benefits, Harms, and Costs Accurate diagnosis of placenta previa may reduce hospital stays and unnecessary interventions.