Vaginal bleeding in women before menstruation can be either pregnancy or menstrual flow. If it is pregnancy, there are several possibilities: first, the patient is normally pregnant with periodic vaginal bleeding. Some women in the clinic have periodic vaginal bleeding in early pregnancy, which is self-limiting, like menstruation; however, it is not normal menstruation, and the patient will have early pregnancy reactions such as nausea, vomiting and breast swelling, and such early pregnancy reactions will persist after the bleeding ends; second, it is considered to be pre-eclampsia If the patient has bleeding before menstruation, the bleeding time is 2-8 days and the amount is the same as the patient’s usual menstrual flow, it should be considered as normal menstruation; the patient does not have early pregnancy reactions such as nausea, vomiting and breast swelling, and even if there is breast swelling before menstruation, the breast swelling will disappear gradually after menstruation.