system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 25-year old woman is brought to the emergency department because of a 1-day history of lower abdominal pain and vaginal bleeding. Her last menstrual period was 6 weeks ago. She is sexually active and uses condoms inconsistently with her boyfriend. She had pelvic inflammatory disease at the age of 22 years. Her temperature is 37.2°C (99°F), pulse is 90/min, respirations are 14/min, and blood pressure is 130/70 mm Hg. The abdomen is soft, and there is tenderness to palpation in the left lower quadrant with guarding but no rebound. There is scant blood in the introitus. Her serum β-human chorionic gonadotropin (hCG) level is 1,600 mIU/mL. Her blood type is O, RhD negative. She is asked to return 4 days later. Her serum β-hCG level is now 1,900 mIU/ml. A pelvic ultrasound shows a normal appearing uterus with an empty intrauterine cavity and a minimal amount of free pelvic fluid. Which of the following is the most appropriate next step in management?
assistant
Administration of anti-D immunoglobulin and intramuscular methotrexate