The first thing you should do is to observe the development of the breast: whether the two breasts are symmetrical; whether the size is similar; whether the nipples on both sides are at the same level; whether the nipples are retracted and depressed; whether there is erosion of the nipples and areolas and what is the color of the breast skin; whether there is edema and cellulite; whether there is inflammation such as redness and swelling; whether there is anger in the superficial veins of the breast area, etc. 1.Visual examination Take off your shirt, under bright light, face the mirror and do bilateral breast visual examination: drop your arms, observe whether the curved contour of both breasts has changed, whether they are at the same height, whether the skin of the breast, nipple and areola has peeling or erosion, and whether the nipple is raised or retracted. Then cross your arms and rotate your body from side to side to continue to observe the above changes. 2.Palpation Take a standing or supine position, put the left hand behind the head, check the left breast with the right hand, fingers together, gradually move clockwise from the top of the breast to check, in the order of upper outer, lower outer, lower inner, upper inner, underarm, and systematically check for lumps. Be careful not to miss any part, and do not press or squeeze with your fingertips. After examining the breast, gently squeeze the nipple with the index and middle fingers to see if there is any blood-tinged discharge. If you find any lumps or other abnormalities through the examination, go to the hospital for further examination. The best time for examination For women with normal menstruation, the 9th to 11th day after menstruation is the best time for breast examination, when estrogen has the least effect on the breast and the breast is in a relatively static state, making it easy to detect lesions. Lumps that appear during breastfeeding should be further examined after weaning if they are clinically suspected to be tumors.