Over the summer, the Equal Employment Opportunity Commission issued new guidance on accommodating pregnant employees. The Pregnancy Discrimination Act doesn't require reasonable accommodation for pregnant employees. That is, unless you accommodate other employees who are not considered to have a disability under the Americans with Disabilities Act. In that case, you need to do the same for pregnant employees. 

Got it? If not, Jeff Nowak has a good discussion focusing on light duty accommodations for pregnant employees.

But, there are situations in which, even if you don't accommodate other non-disabled employees, you still must consider accommodations for pregnant employees. (And I'm not even talking about many state and local laws, which require those accommodations). Indeed, while pregnancy is not an ADA disability, it may result in the onset of another condition that does qualify as an ADA disability and, thus, may require a reasonable accommodation.