Serum prolactin concentrations in women treated with chlormadinone acetate.

Serum prolactin concentrations were measured serially in eight normal women who used continuous chlormadinone acetate treatment (500 mug per day) for six months as part of an investigational new drug contraceptive study. Circulating prolactin was also measured in women using several additional oral contraceptive steroid preparations including a sequential mestranol-mestranol + chlormadinone acetate regimen. No increase in basal serum prolactin concentration was produced by chlormadinone acetate treatment, either alone or when added to estrogen therapy. These results suggest that chlormadinone acetate may not alter human mammary tissue through a prolactin mechanism.