When the menstrual period arrives only a small amount of menstrual blood is brown blood may be endocrine disorders, endometrial lining is too thin, the uterine cavity adhesion and so on. If there is a sudden change in the amount of menstrual flow, it is recommended to consult a doctor to clarify the condition. If the amount of menstruation is usually very small, there is no need for special treatment. 1. Endocrine disorders: When women are in perimenopause, or suffer from polycystic ovary syndrome or hypothyroidism, hormone secretion disorders will occur in the body, resulting in disorders of the menstrual cycle, excessive or low menstrual flow, etc. Perimenopause may be accompanied by hot flashes, polycystic ovary syndrome may be accompanied by hairiness and obesity, etc. Hypothyroidism may be accompanied by hairiness and obesity. Hypothyroidism may be accompanied by chills and fatigue. 2. Thin endometrium: The endometrium is damaged by abortion, scraping and other uterine operations, endometrial tuberculosis and other diseases, or the estrogen is too low, the endometrium is not proliferating enough, and the endometrium is too thin, which will lead to the endometrium peeling off a small amount of endometrium, and there will be a small amount of menstruation, or even amenorrhea. 3. Uterine cavity adhesion: it is mostly a complication caused by abortion, scraping and other uterine operations. If you have recently had uterine operations, and you have low menstrual flow and lower abdominal rise, you can improve the ultrasound or hysteroscopy again to make clear whether there are uterine cavity adhesions and poor menstrual blood flow. If a woman has abnormal menstruation, or accompanied by lower abdominal discomfort, etc., go to the hospital in a timely manner, according to the condition of the doctor’s guidance to take estradiol valerate, dydrogesterone and other estrogenic hormone drug therapy or uterine adhesion separation surgery, etc., do not self-medication, so as not to delay and aggravate the condition.