Shaela Evenson filed the lawsuit Thursday alleging her firing violated federal and state laws that prohibit discrimination based on pregnancy, The Montana Standard reported. She is seeking back pay, benefits, and compensatory and punitive damages.
Evenson taught literature and physical education for grades 6 through 8 at Butte Central Catholic Schools for nine years. She was fired in January after the Roman Catholic Diocese of Helena received a letter about her pregnancy.
School officials referred all questions to the diocese, and a diocesan spokesman did not immediately respond to an email from The Associated Press seeking comment.
Evenson became pregnant through artificial insemination and gave birth to a boy March 7, the first child for Evenson and her partner, Marilyn Tobin.
Evenson was fired for violating the terms of her contract, which required her to practice the tenets of the Catholic faith, said Patrick Haggarty, then the superintendent of schools for the diocese.
The lawsuit says that the district does not investigate male employees and nonpregnant female employees for compliance with Catholic Church teachings.
Evenson's lawyer, Brian Butler, of Cincinnati, won a $170,000 jury award in a similar case in Ohio. He said the case made it clear that an employer, even a religious institution, cannot require an employee to give up certain civil rights as a condition of employment.
Evenson filed a discrimination charge with the federal Equal Employment Opportunity Commission earlier this year.