A 30-year-old woman came to her doctor with a history of amenorrhea (absence of menses) and galactorrhea (the production of breast milk). She was not pregnant and appeared otherwise fit and well.
Serum prolactin was measured.
Prolactin is a hormone produced by the pituitary gland and necessary for the production of breast milk postpartum. This hormone was markedly elevated.
Further clinical tests demonstrated visual field defects.