Diagnosing and Managing Breast Disease During Pregnancy and Lactation.

Although carcinoma of the breast complicates 1:3000 deliveries in the US, most breast conditions unique to pregnancy and lactation are benign--for example, lactating adenoma, galactocele, gigantomastia, and benign bloody nipple discharge. Nevertheless, malignancy must be excluded by a thorough work-up, including breast biopsy if indicated; "watchful waiting" when a breast mass is discovered is no more appropriate than in a nonpregnant patient. During lactation, the major problems encountered often are part of a spectrum of inflammatory and infectious complications. Nasopharyngeal organisms from the infant are usually the source of breast infections in lactating women. Keeping the breast empty of milk promotes healing by helping to drain the culture medium that is facilitating growth of organisms. Hence, the earlier recommendations that breast-feeding cease during mastitis have been superseded by the knowledge that breast-feeding is generally not harmful to the infant and may speed resolution of the infectious process. The diagnosis and management of pregnancy-associated breast cancer (PABC) is reviewed. Pregnancy-associated masses are usually discovered by patient self-examination, and the clinician should proceed to fine-needle aspiration or biopsy, rather than mammography, which has poor sensitivity during pregnancy and lactation because of increased breast density. Management of a new breast mass in pregnancy should maximize diagnostic accuracy and minimize the chances of missing PABC, yet avoid harm to the fetus or interruption of lactation.