Wuhrer, 38, filed the discrimination and wrongful termination suit in Los Angeles County Superior Court. She is alleging she suffered at least $3 million in damages to her earnings, career and through the cost of emotional distress.
Details of the suit were first reported by TMZ.com.
"We have not been served and we do not comment on pending litigation," ABC said in a statement.
Wuhrer played Reese Marshall on the show. According to her suit, she notified the writers and producers that she was pregnant in August so they would have time to write her condition into the script.
Instead, Wuhrer said she was fired two weeks later.
"The vile underbelly of the Hollywood Machine encourages female actors to be as beautiful and slim as possible," the suit said.
It added that an actress who "dares" to become pregnant has one choice: "Terminate her pregnancy or be terminated."
The suit accuses the defendants of sex discrimination, pregnancy-based discrimination, wrongful termination, failure to provide reasonable accommodations for pregnancy and other allegations.