Pregnancy and lactation constitute states of intense hormonal variation with secretory and structural changes in the breast parenchyma. These changes translate into important features on breast imaging, as well as the emergence of specific benign and malignant lesions. This literature review aims to discuss the safety of the use of breast imaging methods (mammography, ultrasound, and magnetic resonance imaging) during the pregnancy-lactation cycle, and to present the expected physiological changes and imaging appearance of the main breast diseases that may occur in this period, such as galactocele, lactating adenoma, fibroadenoma, puerperal mastitis, and pregnancy-associated breast cancer.