Hyperprolactinaemia (BrE) or hyperprolactinemia (AmE)'s the presence of abnormally-high levels of prolactin in the blood. Normal levels are less than 580 mIU/L for women, and less than 450 mIU/L for men. Prolactin's a peptide hormone produced by the anterior pituitary gland primarily associated with lactation and plays important breast development during pregnancy. Hyperprolactinaemia may cause production and spontaneous flow of breast milk and disruptions in the normal menstrual period in wome… (More on Hyperprolactinemia)