Contraception is covered by the Affordable Care Act as a preventive health service, something employers and insurers are generally required to provide at no charge. But the Trump administration developed rules to allow employers to opt out of the mandate if they had religious or moral objections.

A version of those rules was stymied by the courts in 2017, so the administration issued a new set of rules in November, which had been scheduled to take effect on Monday.

However, the judge, Haywood S. Gilliam Jr. of the United States District Court in Oakland, Calif., granted a request by 13 states and the District of Columbia for a preliminary injunction, writing that the new rules “are nearly identical to” the ones that he had previously blocked.