The Huffington Post published a transcript of a telephone conversation between DesJarlais and a patient with whom he allegedly had been having an extramarital affair. The website said the transcript had been under seal as part of a divorce case, and its authenticity had been independently verified.
"You told me you'd have an abortion, and now we're getting to(o) far along without one," the transcript quotes DesJarlais as saying.
"This is old news from the last election cycle that Tennesseans have already widely rejected," a representative for DesJarlais told The Washington Post. "Desperate personal attacks do not solve our nation's problems, yet it appears that there are those who choose to continue to engage in the same gutter politics that were characterized by national media as the nastiest in the nation just two years ago."
"Since the congressman's opponents cannot attack him on his independent, conservative and pro-life record in Congress they have once again resorted to pure character assassination."
DesJarlais was elected to Congress in 2010, benefiting from the Tea Party wave to unseat Rep. Lincoln Davis, a Democrat. He is running for re-election in November in a newly drawn district.
Although he has largely avoided addressing abortion, he told The (Nashville) Tennessean in August he is "a consistent supporter of pro-life values."
Tennessee Right to Life declined to endorse DesJarlais after he did not return a questionnaire sent to candidates this summer, The Tennessean said.
During the 2010 campaign, Democrats cited court documents indicating DesJarlais had threatened suicide and displayed other erratic behavior in a dispute with his then wife.
State Sen. Eric Stewart, the Democratic nominee challenging DesJarlais, told reporters DesJarlais "has proven over and over again that he can't be trusted."