The U.S. Supreme Court last Wednesday sided with a former driver for UPS Inc. by throwing out a lower court ruling blocking her lawsuit accusing the package delivery company of discrimination for refusing to lighten her work duties while she was pregnant.

On a 6-3 vote, the justices revived Peggy Young’s discrimination claim against UPS and sent the case back to a lower court.

The case focused on whether employers must provide accommodations for pregnant workers who may have physical limitations on tasks they can perform. The justices gave Young another chance to litigate whether UPS should have granted her request for temporary changes in work duties—she asked not to lift heavier packages—after she became pregnant in 2006.

Writing on behalf of the majority, liberal Justice Stephen Breyer said the lower court is required to determine if the employer had “legitimate, nondiscriminatory, nonpretextual justification” for treating employees differently.

A federal district court judge and an appeals court had ruled in favor of UPS, which was backed by business groups in the case.

Breyer said the lower court failed to consider the effects of UPS policies that covered non-pregnant workers who might have disabilities, injuries or otherwise might need accommodations, and asked, “Why, when the employer accommodated so many, could it not accommodate pregnant women as well?”

Breyer said there is a “genuine dispute as to whether UPS provided more favorable treatment to at least some employees whose situation cannot reasonably be distinguished from Young’s.”

The two sides in the case disagreed over whether UPS agreed to accommodate non-pregnant workers requesting light-duty assignments.

The case concerned whether the package delivery company violated a federal law, the Pregnancy Discrimination Act, by denying Young’s request. Young, who worked at a Maryland facility, had acted on a midwife’s advice that she not be required to lift packages weighing more than 20 pounds (9 kg).

Conservative Justices Antonin Scalia, Anthony Kennedy and Clarence Thomas dissented, accusing the court majority of going beyond the Pregnancy Discrimination Act and imposing new requirements on employers to offer stronger justifications for workplace policies that could burden pregnant women.

UPS said last October that starting this past January it would begin providing accommodations for pregnant women. The U.S. Equal Employment Opportunity Commission last July issued enforcement guidance saying employers must offer accommodations to pregnant women just as they do for other workers with similar physical limitations.

The case is Young v. UPS, U.S. Supreme Court, No. 12-1226.

(Reporting by Lawrence Hurley; Editing by Will Dunham)