The decrease in menstruation after hysteroscopic surgery is mostly normal. The endometrium of the uterus will be damaged after hysteroscopic surgery, and if the surgery is done on the endometrium, it will easily cause the endometrium to become thinner and the menstrual flow to decrease. If the menstrual flow is getting less and less and there is amenorrhea, this is an abnormal phenomenon, which may be caused by infection in the uterine cavity due to hysteroscopic surgery and intrauterine adhesions, which can easily cause low menstrual flow and amenorrhea, and may also be caused by the decrease of menstrual flow due to the decrease of estrogen. Therefore, if there is a decrease in menstrual flow after hysteroscopy, you need to go to the hospital for examination according to the specific situation and choose the appropriate treatment. Estradiol valerate tablets are needed for low estrogen, and if the uterine cavity is adhered, you need to do a cavity separation surgery.