The case comes at a time when existing maternity and paternity leave policies are under fire.
A battle over pregnant-worker rights is set to take center stage at the U.S. Supreme Court today, as the justices hear arguments in a pivotal case that pits a former United Parcel Service (UPS) driver against the delivery company. The case could have wide implications, given that nearly 40% of all U.S. households are now led by a "breadwinner mom" who serves as the sole or primary source of her family's income.