Causes

Prolactinoma is one type of tumor that develops in the pituitary gland. The cause of these tumors is unknown.

The pituitary gland is a small bean-shaped gland situated at the base of your brain. Despite its small size, the pituitary gland influences nearly every part of your body. Its hormones help regulate important functions such as growth, metabolism, blood pressure and reproduction.

Other possible causes of prolactin overproduction include medications, other types of pituitary tumors, an underactive thyroid gland, ongoing irritation to the chest, pregnancy and breast-feeding.