Change in mammographic breast density associated with the use of Depo-Provera.

We report two cases in which routine mammograms showed a significant increase in breast density compared to previous studies. Review of patient histories revealed that both women had been receiving contraceptive injections of Depo-Provera at the time of their earlier mammograms. Breast density increased after Depo-Provera was discontinued. We postulate that Depo-Provera has a suppressive effect on breast density. Alterations in breast density may have implications regarding breast cancer risk. Etiologies of generalized change in breast density are reviewed.