Mr. Trump removed any doubt about his intentions when he signed the executive order that day. At a ceremony in the Rose Garden of the White House, he celebrated the faith of the Little Sisters of the Poor, a 178-year-old religious order that refused to comply with the contraceptive coverage mandate and fought it all the way to the Supreme Court.
The president invited the Little Sisters to join him on the dais, announced that they “sort of just won a lawsuit” and told them that their “long ordeal will soon be over.”
“With this executive order,” Mr. Trump said, “we are ending the attacks on your religious liberty.”
The new rule will fulfill a campaign pledge by Mr. Trump. “I will make absolutely certain religious orders like the Little Sisters of Poor are not bullied by the federal government because of their religious beliefs,” he said in October in a letter to leaders of Roman Catholic organizations.
Tom Price, the secretary of health and human services, welcomed the opportunity to re-examine the preventive-services mandate. “We will be taking action in short order to follow the president’s instruction to safeguard the deeply held religious beliefs of Americans who provide health insurance to their employees,” he said this month.
Democrats in Congress have vowed to fight just as hard to preserve the mandate, saying it has benefited over 50 million women.
Last week, Senator Patty Murray of Washington and 13 other Democratic senators warned Mick Mulvaney, the White House budget director, to cease efforts that could “undermine access to affordable preventive services, including contraception, for women.”
“Women saved more than $1.4 billion in out-of-pocket costs for birth control in 2013 alone,” the senators said Thursday in a letter to Mr. Mulvaney. “Access to affordable preventive services, including contraception, is a critical part of women’s health care.”
Because the policy change is embodied in an interim final rule, it could take effect immediately upon publication in the Federal Register. When agencies issue interim final rules, however, they typically invite public comments and can later revise the rules in light of those comments.
An official at the Office of Management and Budget declined to discuss the rule, other than to say it was under review.
Gretchen Borchelt, a vice president of the National Women’s Law Center, a nonprofit advocacy group, said she did not know the details of the rule. But she said: “We think whatever the rule is, it will allow an employer’s religious beliefs to keep birth control away from women. We are sure that some women will lose birth control coverage.”
Ms. Borchelt said her organization was preparing a lawsuit to challenge the expected rule, and she cited several possible legal arguments.
If the Trump administration does not adequately explain and justify the rule, she said, it could be challenged as “arbitrary and capricious,” in violation of federal law. In addition, she said, women could challenge it as violating a section of the Affordable Care Act that broadly prohibits discrimination in health programs that receive federal funds.
Ms. Borchelt also pointed to a little-known provision of the Affordable Care Act that says the health secretary shall not issue any rule that “impedes timely access to health care services” or “creates any unreasonable barriers to the ability of individuals to obtain appropriate medical care.”
The American College of Obstetricians and Gynecologists strongly supports the mandate. “Access to contraception is a medical necessity for women during approximately 30 years of their lives,” the group said.
Mark L. Rienzi, a lawyer at the Becket Fund for Religious Liberty who represents the Little Sisters, said the new rule would go a long way to address their concerns. But he said they would still seek a court order to ensure that the government could not impose similar requirements in the future.
President Barack Obama signed the Affordable Care Act in March 2010. In August 2011, his administration required employers and insurers to cover the full range of contraceptive methods approved by the Food and Drug Administration. Facing lawsuits, Mr. Obama proposed variations of the rule intended to lessen the burden on employers with religious objections. For example, he agreed to excuse these employers from providing or paying for contraceptive coverage, while trying to ensure that women enrolled in their health plans would still have such coverage.
The Little Sisters and dozens of other religious groups objected, saying the arrangements still made them complicit in what they believed to be sinful conduct. At the urging of the Supreme Court, the Obama administration considered additional alternatives, but in January, just before Mr. Obama left office, it decided not to change anything.
Researchers say the Affordable Care Act has increased women’s access to contraceptives, including highly effective methods like intrauterine devices and implants. They suggest doing so may have contributed to a decline in unintended pregnancies.