A 25-year-old woman is complaining of fever of 37°C, pain in her lower abdomen, and vaginal discharge. Three days ago, at 10 weeks of pregnancy, an artificial abortion was performed. The cervix is clean, the uterus is slightly enlarged and painful. The uterine appendages cannot be detected. The fornices are deep and painless. Sanguinopurulent discharge is being produced from the vagina. Make the right diagnosis: