Acute abdominal pain in a young woman

A woman in her 20s presented to the emergency department with a one day history of severe lower abdominal pain and vaginal bleeding. Her previous menstrual period was 5 weeks earlier. She was not using any form of contraception, and had no relevant medical, gynaecological, or surgical history apart from a previous caesarean section. On admission, her temperature was 37.4°C. Her heart rate was 100 bpm with a blood pressure of 102/65 mm Hg. Abdominal examination revealed tenderness over the suprapubic region on deep palpation. Speculum examination showed a closed cervical os with no bleeding or retained product of conception. A urine pregnancy test was positive and her serum β human chorionic gonadotropin (hCG) level was 1724.2 IU/L (normal range <5 IU/L). Other laboratory tests showed a haemoglobin level of 114 g/L (normal range 120-160 g/L), white blood cell count of 17.27×10 …