A 28-year-old woman, married, the menstrual cycle is usually regular for 28 days. Her last menstrual period was May 7, 2023 and went to hospital on 14 June, 2023. The chief complaint was “a small amount of vaginal bloody secretion for 3 days”, without abdominal pain. What is the first next examination of this patient? （ ）
选项：

A:Urine hCG test
B:Basal body temperature measurement
C:Routine urine test
D:Cervical mucus smear
E:Diagnostic curettage