According to a recently filed EEOC lawsuit, Dollar General violated Title VII by firing a sales employee because of her pregnancy. More to the point, Dollar General, the EEOC alleges, fired her immediately after she advised her manager of her pregnancy. It listed "health" as the reason for her termination on her separation notice, after advising her of concerns for her safety.
Correlation isn't necessary causation. But when an employee tells you she's pregnant and you immediately fire her for "health reasons"? It sure looks like pregnancy discrimination to me.