Winfrey told Palin she "kind of bristled" when she learned the teen recently told In Touch magazine, "I'm not going to have sex until I'm married. I can guarantee it" and wondered if such a promise was "realistic."
The talk show host told the teen mom, who appeared on Winfrey's show alongside her mother that she was likely setting herself up to fail and asked if she regretted making such an absolute pronouncement.
"Why set yourself up that way? It may be 10 years before you get married. Why set yourself up so that everybody you go out with, you date -- the media is going to be looking at that person, trying to get that person to sell you out, to say, 'Did you have sex or not,'" said Winfrey. "It's nobody's business when you chose to have sex."
Palin gave short answers to Winfrey's queries, saying, "No, I don't," to a question about whether she felt she was setting herself up to fail at keeping her abstinence pledge.
Winfrey told Palin she was "going to give you a chance to retract or ease that statement if you wanted to and not say categorically, 'I'll never have sex until I'm married.' But if you want to hold to that, may the powers be with you. So you're going to hold to that?"
But before Bristol Palin could answer, her mother asked a surprising follow-up question.
"Does that mean you're going to marry pretty young?"
Her daughter mumbled a response, "I don't know, Mom."
Palin, the former Alaska governor who recently took a job as a Fox News analyst, said she was not encouraging Bristol to get married.
"I'm telling her, don't think she has to find a man and marry young. The world is her oyster, and she's going to be able to pursue an education and career and avocation opportunities without a man," said Palin.
Bristol Palin's pregnancy was made public within days of John McCain's announcing he had chosen Sarah Palin as his running mate in the summer of 2008.
She was briefly engaged to the baby's father, Levi Johnston, whom she has recently taken to court to get full custody of their son, Tripp, and ask for increased child support.
Bristol Palin is seeking $1,750 a month from Johnston, according to court documents filed Thursday and reviewed by The Associated Press.
The documents say Bristol Palin is providing nearly 100 percent of Tripp's care, and that Johnston has paid only $4,400 in more than a year.
Rex Butler, Johnston's lawyer, told the AP that his client had tried to give Bristol Palin money for the baby's care on several occasions, but she refused to meet him.