New rules allowing certain employers to opt out of providing health insurance covering birth control should remain blocked, 12 states and the District of Columbia said.

Final rules scheduled to take effect in January exempted employers that object on religious or moral grounds from complying with Obamacare’s so-called contraceptive mandate. A federal district court blocked their enforcement, and the Trump administration appealed.

These exemptions harm both states and women who depend on insurance to pay for their birth control needs, a California-led coalition fighting the rules told the U.S. Court of Appeals for the Ninth Circuit April 15. They are...