Low menstrual volume on the third day is caused by a variety of reasons, as follows: 1, the most common clinical endocrine disorders, if the patient’s body ovarian function is low, low estrogen levels, there will be low menstrual volume, mostly seen in menopausal women; 2, if the body’s prolactin level is relatively high, there will also be low menstrual volume; 3, women with high androgen levels, ovarian polycystic changes can also lead to low menstrual flow; 4. Damage to the endometrium, such as patients who have had multiple abortions, resulting in damage to the basal layer of the endometrium, can also cause low menstrual flow; 5. If there is endometrial tuberculosis, such symptoms can also occur.