Ultrasound is normal, but if there are abnormalities, such as irregular vaginal bleeding and infertility, a hysteroscopy may be necessary. Hysteroscopy is a fiber-optic endoscope. After dilating the uterine cavity with dilatation media, a light-guided glass fiber speculum inserted into the uterine cavity directly observes the cervical canal, the uterine cavity, and the opening of the fallopian tubes, and is able to target diseased tissues for direct sampling and sending to pathology for examination, and can also be used for surgical treatments under the hysteroscope. Ultrasound examination of the uterus and adnexa is a common examination for women, which can detect most of the gynecological diseases, but there are some abnormalities that may not be detected by ultrasound alone. If the ultrasound is normal, but there is abnormal uterine bleeding, unexplained infertility or repeated miscarriages, suspected uterine adhesions or uterine deformities, suspected residual gestational tissues, or foreign objects in the uterine cavity, a hysteroscopy will be needed.