Breast Cancer Screening in Pregnant and Lactating Patients: A Practical Approach

Screening and diagnostic evaluation for breast cancer is increasingly common during pregnancy and lactation due to delayed childbearing and identification of elevated hereditary and familial risk during reproductive years, with patients often undergoing risk assessment beginning at 25 years of age. Although mammography is safe for pregnant and lactating patients, its sensitivity may be reduced because hormonal changes increase parenchymal density and can obscure malignant lesions. US is widely used because it does not involve exposure to ionizing radiation and serves as the primary modality for evaluating symptomatic patients. However, its role in routine screening remains uncertain because evidence regarding screening performance and outcomes in pregnant and lactating populations is limited. MRI is contraindicated during pregnancy but may be performed during lactation for screening of patients at high risk for or with newly diagnosed breast cancer, despite its pronounced background parenchymal enhancement. Timely evaluation of breast symptoms and imaging abnormalities is critical given the rising incidence of pregnancy-associated breast cancer and the potential for delayed diagnosis. Therefore, radiologists must balance diagnostic performance with maternal and fetal safety when selecting imaging modalities. The authors review the current American College of Radiology Appropriateness Criteria and the guidelines of other professional organizations; summarize the epidemiology of pregnancy-associated breast cancer and the physiologic breast changes that affect imaging interpretation; and highlight modality-specific limitations, safety considerations, and contraindications. Strategies for identifying patients at high risk for breast cancer who require continued screening and for effectively communicating imaging risks, benefits, and expectations to patients and referring clinicians are also discussed.