Michigan’s breast density reporting bill, signed into law by Gov. Rick Snyder in January, goes into effect June 1.

The bill says that, when a mammogram shows dense breast tissue, the following must be communicated to the patient:

“Your mammogram shows that your breast tissue is dense. Dense breast tissue is very common and is not abnormal. However, dense breast tissue can make it harder to find cancer through a mammogram. Also, dense breast tissue may increase your risk for breast cancer. This information about the result of your mammogram is given to you to raise your awareness. Use this information to discuss with your health care provider whether other supplemental tests in addition to your mammogram may be appropriate for you, based on your individual risk. A report of your results was sent to your ordering physician. If you are self-referred, a report of your results was sent to you in addition to this summary.”

Michigan was the 21st state to enact such a law, joining Ohio, Missouri, Massachusetts, Rhode Island, Minnesota, Arizona, New Jersey, Tennessee, Hawaii, Maryland, Alabama, Nevada, Oregon, North Carolina, Pennsylvania, Virginia, California, New York, Texas and Connecticut.

In April, North Dakota became state No. 22 when Gov. Jack Dalrymple signed the state’s breast density reporting bill into law.

Nancy Cappello and her advocacy group, Are You Dense, Inc., helped the Michigan bill become law. Cappello founded the nonprofit to increase awareness in 2004, after a gynecologist found advanced cancer that had spread to her lymph nodes. The discovery came only months after she had a mammogram that found no signs of cancer. The experience spurred her to action.

“My radiologists knew about [my dense breast tissue]. My doctor knew about it,” Cappello told the Detroit Free Press. “Everybody seemed to know about it but me.”