Galactorrhoea in Hyperprolactinaemia	

The incidence of galactorrhoea in hyperprolactinaemic patients is between thirty and eighty per cent, depending on the care with which the physician looks for this sign. Approximately fifty per cent of women with galactorrhoea, however, have normal prolactin and, as mentioned below, it is particularly those patients with very high prolactin levels, that is, greater than 100ng/ml (2,000mu/l), who often have no galactorrhoea – thus, it is a poor marker of hyperprolactinaemia. (Normal prolactin levels are below 18ng/ml = 360mu/l.)
In male patients with hyperprolactinaemia, there is usually no gynaecomastia, but milk may be expressed from an entirely normal-sized male breast. 
The incidence of galactorrhoea in men with hyperprolactinaemia is low, however, being less than thirty per cent (i.e. it is much less common than in women).
In patients with extremely high prolactin levels, galactorrhoea may not be found.