This morning's Wall Street Journal has a piece on the growth of EEOC pregnancy discrimination charges. According to the Journal:
Pregnancy-bias complaints recorded by the Equal Employment Opportunity Commission surged 14% last year to 5,587, up 40% from a decade ago and the biggest annual increase in 13 years.... The groundswell reflects both changing demographics and a new activism among mothers. It also shows that even now, 30 years after passage of the federal Pregnancy Discrimination Act, there is still confusion about what protections it provides. "I thought we were protected," said an advertising executive during a recent gathering of 100 working mothers. "Then I find out we can be fired while we're pregnant, employers can refuse to hire us -- what exactly are our rights?"
While employers can indeed fire, lay off or refuse to hire pregnant women, they can't single them out for worse treatment -- and they must be able to prove they held men to the same standards or asked male job candidates comparable questions.... Many women who bring complaints are surprised to learn that they don't have special protection from adverse treatment. One manager for a publishing company thought she was being discriminated against when her employer fired her for poor performance while pregnant, says Kimberlie Ryan, a Denver employment attorney. In fact, the manager couldn't prove her bosses knew she was pregnant when they decided to fire her, says Ms. Ryan. To succeed in a claim, a woman generally must be able to prove an adverse action was motivated by her pregnancy or her status as a mother.
Let me suggest that if you decide to fire an employee for poor performance while that employee is on maternity leave, you have a well-documented paper trail of issues, and that the first the employee will be hearing about these issues is not during the termination. Otherwise, it will be difficult to overcome a claim that the performance problems were invented as a pretext to terminate a pregnant employee.