Nipple Discharge

Nipple discharge – the release of fluid from the nipple – is very common. This is the third most common reported breast problem after lumps and tenderness.

There are 15–20 milk ducts opening onto each nipple. Discharge can come from one or more of these ducts. Nipple discharge can:

• be spontaneous (fluid is secreted from the nipple without any squeezing of the nipple or pressure on the breast), or

• be on expression (fluid is secreted from the nipple when the nipple is squeezed or there is pressure on the breast)

• come from one breast (unilateral) or both breasts (bilateral)

• be clear, yellow, milky, brown, green, or bloodstained in appearance

• originate from one duct (one opening on the nipple) or more than one duct

Physiological nipple discharge

Discharge of fluid from a normal breast is referred to as ‘physiological discharge’. It is usually yellow, milky, or green in appearance, does not occur spontaneously, and often originates from more than one duct. Physiological nipple discharge is no cause for concern. Milky nipple discharge is also normal during pregnancy and breastfeeding.

When is nipple discharge abnormal?

Spontaneous nipple discharge unrelated to pregnancy or breastfeeding is considered abnormal. In most cases it has a benign (ie. noncancerous) cause, and is more likely to be unilateral, confined to one duct, and clear or bloodstained in appearance. Nipple discharge associated with other breast symptoms such as a lump, ulceration, or inversion of the nipple requires prompt investigation.

Breast cancer

Breast cancer is an uncommon cause of nipple discharge. Few women with breast cancer have nipple discharge, and most have other symptoms, eg. a lump or newly inverted nipple. Breast cancer that causes nipple discharge is likely to be benign or early invasive breast cancer rather than advanced breast cancer.