Gov. Bob McDonnell (R) has signed a bill requiring that radiologists provide information about breast density in post-mammogram letters to patients.

The measure goes into effect July 1.

Virginia Gov. Robert McDonnell (R). (J. Scott Applewhite/AP)

The bill was met with behind-the-scenes resistance from radiologists who were concerned that women would be unduly alarmed, turned off from life-saving mammograms, and left footing the bill for unnecessary and expensive tests. They succeeded in changing the proposed language so that it would alert women to density but not suggest that they seek other tests.