What if the employee works in a field where physical activity is a job requirement, such as law enforcement?
Those are tricky questions across the nation right now — and even here in Northern Kentucky, where a police officer is fighting to work off the streets until she gives birth.
When Officer Lyndi Trischler became pregnant with her son early this year, she didn't think it would be an issue. During her first pregnancy, the Florence Police Department let her work a desk job after being on patrol had become physically impossible.
So Trischler, 30, notified her supervisors of her second pregnancy and continued working her 10-hour shifts out on patrol. By June, however, her five-months-pregnant belly was outgrowing her bulletproof vest, and her heavy gun belt had become uncomfortable.
She began having heart palpitations during what was already a stressful time: Her unborn son has a rare bone disorder and is not expected to survive long after birth.
After consulting with her doctor, Trischler asked her supervisors for modified duty.
This time, however, the city of Florence said no.
The city always had a policy that only employees injured on the job were eligible for modified duty, according to an internal memo. It had previously made exceptions to that policy, including for Trischler's first pregnancy last year.
In April 2013, the city stopped allowing those exceptions. The memo doesn't say why, just that employees with disabilities not incurred on the job must take sick, vacation or unpaid leave if they can't perform their jobs.
Trischler and her attorneys believe the change was made in response to her first pregnancy. They have filed a federal discrimination complaint with the U.S. Equal Employment Opportunity Commission, accusing the city of violating both the Americans With Disabilities Act and the Pregnancy Discrimination Act.
City officials won't discuss pending litigation, and City Attorney Hugh Skees said Florence disagrees with the complaint.
"We've seen it," he said. "We don't agree with it, but we respect the officer's right to bring it, and we'll follow the process in the EEOC and bring our defense."
Trischler is represented by A Better Balance, a national group that advocates for working families and tries to raise awareness of situations like hers.
"A lot of employers are doing the right thing. But then there are the employers who are not, and it disproportionately affects low-wage workers, those with physically demanding jobs and those in traditionally 'male' occupations," said her attorney, Elizabeth Gedmark.
Last month, the EEOC issued new guidelines to clarify that employers are required to provide "reasonable accommodations" to pregnant women and cannot treat them differently than workers injured on the job.
Trischler is one of just two women on a police force of 64 officers in Florence, which is known as one of the region's best-run municipalities.
Similarly sized cities, including Covington and Erlanger, allow pregnant police officers to work on modified duty, according to officials in those cities. Short-term disability leave is also provided.
Florence added short-term disability leave July 1, though Trischler said she's had trouble getting her claim approved since her last day on patrol was June 28.
She said city officials are working with the insurer on her behalf, however, and they've also allowed her to keep her health insurance as long as she pays the premiums.
The city also offers sick and vacation benefits to help out in situations like this one; someone like Trischler, who's been with the city for two and a half years, would accrue four weeks of paid vacation during a typical year.
Trischler, who holds a master's degree in criminal justice, said she doesn't have a grudge against the Florence department or the city itself, just against the policy that prevents her from working on modified duty.
Until the matter is resolved, however, she isn't in uniform. She's taking vacation and sick leave so she still receives a paycheck, and her fellow officers have donated 180 hours of their own time to help her out.
Once that runs out, however, she'll be on unpaid leave and relying on the income of her boyfriend, Adam, a police officer who commutes about an hour and a half to his job.
Trischler expects to deliver their son in nine weeks, when doctors believe he'll have the best chance to be born alive.
Under the federal Family and Medical Leave Act, her job is protected: She'll be able to return to work when she is physically able to do so, likely six weeks after her son is born. But that time, too, will be unpaid, since she's using up her vacation and sick time now.
Trischler said she loves her job and her colleagues, but she's unsure if she'll stay with the department.
"I don't know, honestly," she said. "I think that I could, especially if this (policy) gets changed. But I do want another baby — we wanted two babies, and we're going to have one."
Her attorney said they'd prefer to work something out with the city, but officials haven't been responsive.
"Here you have a police officer with a master's degree in criminal justice, obviously very qualified, very hardworking — I would think the city would do everything it could to retain somebody like that," Gedmark said.