Transvaginal ultrasound is a breakthrough technology in the application of obstetrics and gynecology in recent years. It can clearly display the internal organ and tissue structure of the female pelvis without filling the bladder compared with traditional transabdominal ultrasound, and has the characteristics of early and accurate diagnosis of normal and abnormal pregnancy and gynecological diseases. The clinical significance of transvaginal ultrasound: abnormal findings: (gynecology) i. endometrial sonography of normal menstrual cycle and mature and immature follicles in normal ovaries (so-called “ovulation testing”) ii. benign uterine tumors iii. malignant uterine tumors iv. non-bulky ovarian cysts v. ovarian tumors (obstetrics) i. early and definite diagnosis Early Pregnancy II. Abnormal early pregnancy, especially ectopic pregnancy (i.e. “ectopic pregnancy”) is of particular significance because ectopic pregnancy is a clinical emergency and can lead to death if not rescued in time! People who need to be examined: pregnant women in labor and delivery or gynecologists who need to assist in the diagnosis of uterine ovarian diseases.