Serum prolactin concentrations related to copper or inert intrauterine devices (IUDs) in women.

A report that serum prolactin concentrations were almost doubled by the use of copper IUDs led us to study the effect of both copper and inert IUDs. We studied 105 normal women in whom all other prolactinergic factors had been excluded; 25 of them were using copper IUDs, 25 were using inert IUDs and there were 55 controls. No differences were found in the mean prolactin levels between these groups (4.3, 4.5 and 4.3 microgram/l, respectively). We conclude that copper and inert IUDs do not affect prolactin secretion.