During the menstrual cycle, due to the influence of various related endocrine hormones, the mammary glands will undergo some physiological hyperplasia and regeneration changes, resulting in the breast tissue being in different degrees of congestion and edema, and these changes may interfere with the doctor’s examination of the location, size, and nature of the breast lumps, which in turn affects the judgment of the nature of the breast lumps. So, what is the most appropriate time to check? The best time to check the breasts is around the 9th to 10th day of menstruation or 3-7 days after menstruation, when the effect of estrogen on the mammary glands is minimized, the mammary glands are in a relatively static state, and breast lesions or abnormalities can be easily detected. Post-menopausal elderly women can choose the time for breast examination as they are less affected by endocrine hormones due to the decrease of estrogen in their body. However, you should be reminded that the high incidence of breast cancer is between the ages of 45 and 55. If breast lesions are detected during breast self-examination or screening, you should seek early medical attention and follow the doctor’s instructions for follow-up. Some patients do not undergo regular checkups for a long time after the clinical remission of benign breast disease, and when the original benign lesions become malignant, it will be very difficult to cure them. Therefore, early consultation should be an important principle, and choosing the best time for consultation is an important means to improve the correct diagnosis rate.