Diana Falzone, 34, said in the lawsuit in New York state court that despite writing many popular articles for Fox News' website and routinely being praised for on-air appearances, she was abruptly sidelined in January, three days after the article about her struggle with endometriosis was published.
Falzone said Fox, a unit of Twenty-First Century Fox Inc, discriminated against her on the basis of sex and disability in violation of New York City law.
The network did not immediately respond to a request for comment.
Fox News has faced mounting legal claims that it ignored employees' complaints of sexual harassment and gender and race discrimination.
Bill O'Reilly, the network's most popular anchor, and former Fox News chief Roger Ailes both have been ousted over harassment claims by several women, which they deny.
“Once Diana disclosed her condition, Fox executives decided she no longer conformed to their image of on-air women as ‘physically perfect,’” Nancy Smith, Falzone's attorney, said in a statement.
Smith and Martin Hyman filed a sexual harassment lawsuit last year against Ailes on behalf of former Fox News anchor Gretchen Carlson. The lawsuit, which was settled for $20 million, led to Ailes' resignation after two decades as one of the most influential executives in cable television.
Last week, Fox News anchor Kelly Wright, who is black, and several other non-white employees filed a lawsuit seeking class action status, claiming they were mocked and humiliated because of their race and paid less than white coworkers. Fox has denied the claims.
Fox News announced on Monday that Bill Shine, co-president of the network since August, has resigned. A Fox News contributor sued Shine last month, accusing the executive of failing to investigate her claims of sexual harassment.