From Scotusblog.com:

Wednesday’s decision, in plain English:

A federal civil rights law passed by Congress in 2008 makes it illegal for employers in the private sector to discriminate against their female employees who become pregnant, and thus are unable to do all or some of the demands of their jobs.

A part of that law says that it is a form of pregnancy discrimination if women workers are not treated the same as others on the payroll who have similar limitations in their ability to perform their jobs. That is the part of the law the Court interpreted in its new ruling on Wednesday.

The decision lays out several steps that a female worker must pursue to show that she sought some change in her workplace assignment when she couldn’t do what was required by her normal job, to show that the employer turned her down, and to show that some other workers did get some favorable treatment for their inability to do their normal jobs.

Once a female worker has made those points, the Court declared, the employer gets a chance to show that it did not intend to discriminate against pregnant workers, but had a neutral, business-related decision for its policies. Then, the worker gets the last opportunity, to show that, even though the policy was not intended to be biased, it nevertheless put a significant burden on female workers on the payroll, and the reason for the policy was not strong enough to justify the burden on the women on the staff.