Nipple pain before menstruation may be caused by edema, premenstrual tension syndrome, breast enlargement and so on. 1. Edema: The level of estrogen in the body will be high before menstruation, which will stimulate the expansion of breast blood vessels and cause breast edema, which will produce the symptom of nipple pain. 2. Premenstrual tension syndrome: Before menstruation due to sex hormone stimulation, some people will have breast pain, headache and other symptoms. 3. Mammary gland hyperplasia: women due to the imbalance of the ratio of estrogen and progesterone, breast sex hormone receptor quality and quantity of abnormalities, elevated prolactin and other influences lead to mammary gland hyperplasia, the patient will have breast pain nipple pain symptoms. There are more reasons for nipple pain half a month before menstruation, and timely medical attention and treatment are recommended for serious cases.