A 28-year-old woman, 6 weeks amenorrheic, presents with sudden onset unilateral lower abdominal pain and vaginal spotting. Her last menstrual period was 6 weeks ago. Her blood pressure is 90/60 mmHg, heart rate 105 bpm. A urine pregnancy test is positive. What is the most appropriate next diagnostic step?
✓ Correct Answer: Option A
Given the symptoms (amenorrhea, pain, spotting, positive pregnancy test) and hemodynamic instability suggestive of rupture, an ectopic pregnancy is highly suspected. A transvaginal pelvic ultrasound is the most appropriate immediate diagnostic step to confirm pregnancy location.