It is generally not recommended to do mammography during menstruation. Breast diseases have special characteristics and the timing of the examination is related to the menstrual cycle. During different periods of the menstrual cycle, the mammary glands will undergo some physiologic changes of proliferation and rejuvenation under the influence of various related endocrine hormones. In the premenstrual period when the estrogen level is higher, the proliferation of glandular tissue in the breast will be more obvious, the breast tissue will have different degrees of congestion and edema, and the whole breast will be thicker. Some examinations are inappropriate and will affect the judgment of the nature of the breast lump. Mammogram will be painful, so it is not recommended to do mammogram during menstruation, the time to do mammogram is the 5th-10th day after menstruation.