Prior to menstruation, if there is mild, bilateral breast swelling and pain, it is mostly a normal condition that usually occurs 2-3 days before menstruation. However, if the swelling and pain are obvious, with unilateral pain, tingling, severe pain, nipple overflow, lumps to touch and other abnormalities, you need to consider breast-related diseases, PMS and other pathological factors that cause it. I. Physiological factors: changes in the breast and the physiological cycle, hormone levels are closely related to the premenstrual period because of the obvious changes in sex hormones, some people can have a slight swelling and pain in the breast before menstruation, but also accompanied by irritability, emotional instability and other situations. If these abnormalities appear with each regular menstruation, disappearing and subsiding with menstruation, it is normal, and when the breast swelling and pain is tolerable, it generally does not need treatment. Second, pathological factors: 1, breast disease: if accompanied by nipple overflow, local uneven pain, palpable swelling and other symptoms, it may be related to breast hyperplasia, breast fibroids, etc., need to pay attention, timely medical care, improve ultrasound examination for diagnosis; 2, premenstrual syndrome: is a recurrent cycle in the luteal phase, characterized by emotional, behavioral and somatic disorders syndrome, the onset The causes are related to psychosocial factors, ovarian hormone imbalance, neurotransmitter abnormalities and vitamin B6 deficiency. The main symptoms are headache, back pain, breast pain, constipation, edema, loss of motor coordination, irritability, anxiety, depression, and emotional instability 1-2 weeks before menstruation. The disease needs to be treated promptly to prevent damage to various aspects such as physiology and psychology. At the same time, women should wear well-fitting and comfortable underwear in general and keep their emotions stable during menstruation, and should not be overly angry or depressed. Limit the intake of salt and coffee, and exercise moderately. Learn breast self-examination, 9-11 days after the onset of menstruation to check whether there is a depression of the nipple, whether there are changes in the skin of the breast, and whether there are enlarged lymph nodes in the clavicle and armpit, etc., so that diseases can be detected early for prevention and treatment.