If placenta previa or placental abruption is suspected, which initial investigation is indicated?

• A. Ultrasound
• B. MgSO4
• C. CT scan
• D. Bimanual exam

Answer: (A)

When placenta previa or placental abruption is suspected, the first step is ultrasound imaging. Ultrasound safely and quickly shows the placenta’s location relative to the cervical os and assesses fetal well-being, helping distinguish previa (placenta overlying or near the os) from a normal placental position and identify signs of abruption such as a retroplacental hematoma. This guides management without risking harm—especially since a digital vaginal exam is contraindicated if previa is possible, until ultrasound rules it out. Other options aren’t diagnostic first steps: a bimanual exam can provoke heavy bleeding if previa is present; magnesium sulfate is a treatment (neuroprotection or seizure prophylaxis), not an imaging test; CT involves radiation and is not used initially for placental problems.