Ultrasound can be done during menstruation, although it is not recommended to do gynecological examination during menstruation, because during menstruation the endometrial lining will form a traumatized surface, and ultrasound examination at this time may cause infection. However, sometimes ultrasound examination needs to be done during menstruation, so as to facilitate the diagnosis of diseases. The items of ultrasound examination during menstruation are as follows: 1) Sex hormone six examination, which needs to be examined in the 2nd-3rd day of menstruation. 2) Follicle monitoring, which also needs to be examined in the 2nd-5th day of menstruation. 3) Checking of the condition of endometrial lining, such as the thickness checking, for example, the presence of cyclic hyperplasia in the endometrium. The results are also accurate during menstruation. In addition, if there is irregular vaginal bleeding accompanied by abdominal pain, you should not wait until after menstruation to check, otherwise the condition will be delayed.