You can’t. OK, that’s an overstatement; there are times it might make sense, but it is always a high-risk move.
What is the most important factor in whether an ex-employee files a lawsuit against an employer? Anger? Feeling unfairly treated? Need for money? Those are all way up there. But I think the top reason lawsuits are filed is that the ex-employee consults with a lawyer.
When you fire a pregnant employee, she is going to tell her co-workers, spouse, girlfriend or boyfriend, mother, father, grandparents, cousins, brothers and sisters-in-law, neighbors, best friends, casual friends, Facebook friends, acquaintance at the dog park, gym . . . you get the picture. EVERYONE she talks to will say “They can’t do that!” and urge her to see a lawyer.
Although “everyone” is wrong about whether you can fire a pregnant employee, there are a lot of laws that come into play. Some laws require favorable treatment such as time off when the employee is sick or disabled because of the pregnancy. Some laws prohibit treating the pregnant employee differently because of the pregnancy. For example, you cannot discharge an employee because she is pregnant.
To make matters worse, if the soon-to-be mother files a lawsuit, she is likely to find an audience with a very sympathetic jury and judge.
The likelihood she will consult with a lawyer at everyone’s urging, the complexity of the applicable laws. and the fact she will be a sympathetic plaintiff combine to make discharge a high-risk move.
This does not mean an employer’s hands are tied. There are steps to reduce you can take to reduce the risk of litigation. You could some things like making sure (a) you are aware of all applicable laws regarding pregnant employees and have documented proof of compliance with all these laws; (c) you have documented proof that the pregnant employee understood your expectations; (d) you have documented proof she not meeting your expectations; (e) you have documented proof that you gave her a meaningful opportunity to improve and the necessary tools to do so; (f) you notified her in writing that failure to meet expectations would result in discharge; (g) you use progressive discipline; and (h) you have documented proof that similarly-situated non-pregnant employees have been treated the same way as the pregnant employee.
Your goal is to build such an air-tight case that even an opposing lawyer or sympathetic juror or judge looking at the evidence feels compelled to rule in your favor. You are also trying to treat her in a way that almost agrees with the discharge decision. You would like her to feel so comfortable with the result and the overall process that her inner voice telling her that she was treated well is loud enough to drown out the voices that tell her she must see a lawyer.
Even under the best situation, though, I think discharging a pregnant employee will always be a high-risk move for employers.