Breast lumps detected during pregnancy are generally benign and reflect fibroadenoma, lactating adenoma, cysts, infarction of the breast or galactocele. Although rare, the possibility of breast cancer must also be considered to avoid any delays in diagnosis. After patient questioning and clinical examination, the first imaging modality to use is ultrasound. No further assessment is called for if lesions are categorized as BI-RADS 2 and no suspicious clinical signs are observed. Depending on the clinical setting, lesions classified BI-RADS 3 require monitoring and mammographic assessment (which can be helpful in diagnosing cancer and incurs no risk to the embryo or fetus). If the clinical signs are unclear and/or the lesion(s) are categorized as ≥ BI-RADS 4a, then mammography and often biopsy should be performed. Strict BI-RADS scoring (American College of Radiology) should be applied, bearing in mind that benign lesions can appear suspicious during pregnancy, and some cancers can exhibit what seem to be reassuring characteristics.