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 primigravida, 29-year-old woman presents in her 28th week of pregnancy for evaluation of 3 hours of vaginal bleeding and abdominal pain. She denies any trauma and states that this is the first time she has had such symptoms. Her prenatal care has been optimal and all of her antenatal screenings have been within normal limits. Her vital signs are unremarkable. Physical examination reveals a small amount of blood in the vaginal canal and the cervical os is closed. Ultrasound imaging demonstrates positive fetal cardiac activity. What is the most likely diagnosis?
assistant
Threatened abortion