Missouri’s New Mammography Law Led to a 45% Jump in Screenings

Sometimes, access comes down to language. And in Missouri, a few key words made all the difference.

In January 2024, the state implemented a law that expanded insurance coverage for mammography, not by reinventing policy, but by removing ambiguity. The law clarified that insurers must cover diagnostic imaging, including follow-up mammograms and ultrasounds, when needed after an initial screening. In other words, it closed a loophole that left too many women paying out-of-pocket just to understand their own results.

The results speak volumes. According to a new study presented at the 2024 Society for Imaging Informatics in Medicine annual meeting and reported by AuntMinnie.com, diagnostic breast imaging rates in Missouri rose by 45 percent following the law’s implementation, a direct outcome of policy aligning with patient need.

Before the law, Missouri patients were often blindsided. They’d get a screening mammogram covered by insurance, but when the results came back unclear or flagged for further review, the next step, diagnostic imaging, wasn’t always covered. That left many women in a bind, choosing between bills and answers.

The research team from Washington University in St. Louis analyzed over 167,000 imaging exams and found that after the law went into effect, the proportion of women receiving diagnostic mammography rose from 8.2 percent to 11.9 percent. Ultrasound use jumped from 2.6 percent to 3.7 percent. According to study author Jesse Liu, MD, “This suggests the legislation did indeed increase access to important breast imaging.”

And the impact was greatest where it mattered most: among women who had abnormal results and needed clarification. According to the article, those patients were "more likely to undergo additional testing after the law took effect," showing how removing cost as a barrier directly improved follow-through.

For patients and advocates alike, this law is proof that better outcomes often begin with removing red tape. By bridging the gap between initial screening and diagnostic clarity, Missouri gave women permission to keep seeking answers without financial penalty.