Case-control study of galactorrhea and its relationship to the use of oral contraceptives.

A case-control study was performed to determine the relationship between galactorrhea and the use of oral contraceptives as well as other risk factors. The cases included all 109 Olmsted County residents who satisfied the diagnostic criteria for galactorrhea between 1970 and 1980. Control subjects were selected from a sampling frame of all medical registrations and matched to the cases by age, year, and residency. Pituitary adenomas were strongly associated with galactorrhea, as the relative risk was 23.2 (95% confidence interval 2.0 to 90.0). In galactorrhea cases without pituitary adenomas there was an association with oral contraceptives (ever use versus never use), as the relative risk was 2.3 (95% confidence interval 1.3 to 4.4). Among current users of oral contraceptives, the risk of galactorrhea was not increased, but there was a trend of diminishing risk with duration of use. The estimate of relative risk was 3.1 after discontinuation of oral contraceptive use and was highest for the first year after discontinuation (5.5), compared with a year or more after discontinuation (2.1). Thus, galactorrhea was associated with the cessation of oral contraceptives.