When you are not breastfeeding, fluid leaking from one or both nipples is called nipple discharge. It may or may not be a sign of a medical problem.
Nonspontaneous discharge that occurs only when you press on your nipple is usually normal and occurs in the majority of women at one time or another. The discharge can be clear, cloudy, white, yellow, green, or brown. The more the nipple is pressed or stimulated, the more fluid is discharged. This type of nipple discharge does not usually mean that there is a problem.
Spontaneous discharge of fluid or blood from a nipple is a concern, except during pregnancy and breastfeeding. This type of discharge occurs without pressing or stimulating the nipple. Galactorrhea is one type of spontaneous nipple discharge. It may be a side effect of a medicine or caused by a noncancerous tumor in the pituitary gland(pituitary adenoma), decreased thyroid function (hypothyroidism), or certain types of cancer.
Call your doctor if you have spontaneous nipple discharge or a discharge from only one nipple (unilateral) or that looks like blood.