The most clear-cut forms of pregnancy discrimination occur when an employer refuses to hire an applicant because she is pregnant or fires an existing employee because she becomes pregnant. But there are more subtle, but no less prohibited, forms of pregnancy discrimination, such as in the areas of accrual and crediting of seniority, compensation, leave from work, health insurance, and other fringe benefits. Although pregnancy is in many ways a unique condition, a rule of thumb for employers is that they may not treat pregnant employees adversely as compared with employees having comparable temporary medical conditions.

If, because of her pregnancy, an employee is temporarily unable to work, she must be treated like any other temporarily disabled employee. This standard does not render an employer powerless to require anything of the employee, but the approach must be even-handed. For example, if the employer normally requires a doctor's statement verifying an inability to work, the same can be required of a pregnant employee.

If the employer has a policy allowing temporarily disabled workers to ease back into work with modified tasks or different assignments, similar flexibility must be shown to the pregnant worker. If an employer generally holds open a job for a certain period of time for someone out on sick leave or disability leave, a pregnant employee is entitled to such treatment, no more or less.

Ironclad rules are more likely to expose companies to liability under the federal discrimination law. A rule requiring a pregnant employee on leave to stay on leave until the baby is born, regardless of whether she may have recovered from the condition related to the pregnancy, invites a lawsuit. Employers also cannot have a policy that prohibits an employee from returning to work for a predetermined time period after giving birth.