From the article:

The new law drops coverage of most abortions from existing policies -- even to terminate a pregnancy resulting from rape or incest. Women who buy their own individual policies, rather than getting coverage through an employer-based plan, won't be able to purchase the additional coverage, called an abortion rider, from Michigan insurers.

Opponents dubbed the law "rape insurance," arguing that women would have to anticipate the possibility of being raped and purchase the insurance before the assault.

Michigan's Republican-controlled state legislature first passed the measure in 2012, but Gov. Rick Snyder (R) vetoed it, arguing that it wasn't "appropriate to tell a woman who becomes pregnant due to rape that she needed to select elective insurance coverage." Undeterred, Right To Life Michigan gathered 300,000 petition signatures supporting the measure, igniting the infrequently-used citizens initiative process. Both houses of the legislature passed the measure in December. There's no veto in the citizens initiative process, and Snyder's signature was unneeded for the law to go into effect.