Nipple discharge in women. Is it cause for concern? Nipple discharge is one of the most common breast complaints in women. Galactorrhea (milky discharge) may occur during pregnancy or breast-feeding or as a result of drug therapy, hypothyroidism, or hyperthyroidism. Nonbloody discharge is most common and is usually benign. Bloody discharge should be considered a sign of cancer until proved otherwise. Persistent galactorrhea and nonbloody discharge can be treated by transecting the mammary ducts. Simple mastectomy may be appropriate in patients with persistent bloody discharge who have a strong family history of breast cancer. 