While many scholars rightfully have critiqued the Pregnancy Discrimination Act (“PDA”) as falling short of achieving the ultimate goal of equal employment opportunities for women, this Article reveals one of the PDA’s most important successes. By recognizing pregnant women as a “given” in the workplace, the PDA launched a quiet revolution in the way that judges make causal attributions for adverse employment outcomes. Specifically, the PDA provided judges with the conceptual tools that were needed to help shift causal attributions to an employer, rather than attributing a pregnant woman’s struggles in the workplace to her own decision to become a mother. Because our notions of responsibility follow our notions of causation, this shift in causal attribution enabled judges to more easily identify employers as legally responsible for the misfit between the conventional workplace and working women’s lives. While this causal attribution shift has been incomplete, it at least laid the foundation for ongoing conversations about how the law might achieve even deeper structural and organizational transformations in the workplace looking forward. By revealing the PDA’s causation transformation story, this Article seeks to shore up that foundation for future efforts at designing workplaces more fully around a caregiving worker norm.