Imaging the Breast in Pregnant or Lactating Women

Abstract

To describe the imaging evaluation of common benign and malignant breast lesions encountered in pregnant or lactating women. There is increasing prevalence of pregnancy-associated breast cancer as the age of women during pregnancy increases. Women in the first 10 years following pregnancy demonstrate an elevated risk for breast cancer compared to the average population. MRI has been shown to be more sensitive for evaluating the extent of disease in lactating patients than mammography or ultrasound. The hormonal effects of pregnancy and lactation on the breast lead to distinct physiologic changes and pathologic lesions, which can manifest in unique imaging appearances. Most patients will undergo ultrasound for primary diagnostic evaluation. While mammography is not routinely utilized, it is not contraindicated even in pregnancy given the negligible radiation dose to the fetus. While most detected lesions are benign, pregnancy-associated breast cancer (PABC) is a rare diagnosis that must always be excluded. Women with PABC have a worse prognosis than age-matched controls partly due to delay in diagnosis. Thus prompt and accurate work-up of PABC is critical to improve outcomes.