In papers to be filed in a New York court, she said that after Haynesworth, 28, found out about the pregnancy in late February, he promised to "emotionally and financially support" her.
But "after making such promises ... Haynesworth has abandoned the pregnant Silvia Mena ... He has refused to provide any emotional or financial support of Silvia Mena or his unborn child."
The documents claim that Haynesworth -- who signed a $100 million contract with the Redskins last year -- refused to talk to Mena from late March.
Haynesworth's assistant reportedly suggested the dancer "seek treatment from an NFL physician," but Mena feared "some effort might be made to purposefully make her lose the child," the papers said.
"It is very stressful. I cry all the time," Mena said Tuesday.
Her lawyer, Salvatore Strazzullo, said he was filing the $10 million suit Wednesday in Brooklyn Supreme Court.
"This man is worth millions," Strazzullo said. "She has had to apply for Medicaid to take care of her pregnancy."
Haynesworth's agent declined to comment on the claims.