Review Question - QID 214954

A 26-year-old woman presents to the emergency department with 1 day of vaginal bleeding and lower abdominal pain. The pain is most pronounced in the lower abdomen and has gotten worse over the past day. Her last menstrual period was 7 weeks ago. She denies any recent abdominal or vaginal trauma. She has no other past medical history and takes no medications. She uses a copper intrauterine device and is in a monogamous relationship. Her temperature is 99°F (37.2°C), blood pressure is 79/50 mmHg, pulse is 135/min, and respirations are 20/min. Physical examination is notable for diffuse abdominal tenderness upon palpation. Pelvic examination demonstrates uterine and adnexal tenderness and uterine bleeding. Laboratory studies are shown below:

Hemoglobin: 9.5 g/dL
Leukocyte count: 6,000/mm^3
Serum beta-human chorionic gonadotropin (hCG): 2,700 IU/L

The patient is started on intravenous fluids. Which of the following is the most appropriate next step in management?