There is no legal reason why an employer cannot schedule a performance review as it sees fit, and there are legitimate business reasons why an employer may find it beneficial to conduct a performance review after any type of leave. The employee might also find that the purpose of the review was to help her -- that problems were identified with her performance during her leave, or following her return, and that the unscheduled review is meant to give her an opportunity to get back on track before the regular, annual review occurs.

There is nothing inherently improper about the employer's action and, absent evidence that it was improperly motivated, the employee needs to take a wait-and-see attitude. If the employee is convinced that this is a set-up, or was done in retaliation for her taking maternity leave, she can consult a plaintiff-side employment lawyer about the situation, and find out what steps she can take to protect her rights.