By WILL WEISSERT
Associated Press

WASHINGTON (AP) - Elizabeth Warren is standing by her account of being fired from a teaching job nearly 50 years ago because she was pregnant - an anecdote that she routinely recounts at campaign events but one that some conservatives charge has been embellished to make the narrative more compelling for her presidential run.

In a campaign speech she repeats at town halls while crisscrossing the country, the Massachusetts senator tells of graduating from the University of Houston and being hired by the Riverdale Board of Education in New Jersey as a speech pathologist during the 1970-71 school year. She says she'd planned to continue teaching but got pregnant and, once she began showing, "The principal did what principals do: Wished me luck, showed me the door and hired someone else for the job."

Warren has used nearly identical retellings of the story dozens of times, including at rallies in Nevada and California last week, and wrote similarly of the experience in her 2014 memoir. She's enjoyed a steady rise in recent polls to emerge as one of the Democratic presidential primary's front-runners, along with former Vice President Joe Biden.

On Monday, though, Fox News reported on a video of a 2007 interview Warren gave at the University of California at Berkeley where she offered a different account of leaving teaching - suggesting it was by choice.

"I worked with the children with disabilities. I did that for a year, and then that summer, I actually didn't have the education courses, so I was on an 'emergency certificate,'" she says in it. "I went back to graduate school and took a couple of courses in education and said, 'I don't think this is going to work out for me.' I was pregnant with my first baby, so I had a baby and stayed home for a couple of years, and I was really casting about, thinking, 'What am I going to do?'"

The discrepancy is important since the story is one of the core pieces of Warren's campaign message: how she was raised poor in Oklahoma and never intended to go to law school, become a professor at Harvard and eventually run for the Senate and the presidency - and how she may never have done any of that had she been allowed to remain a teacher.

Warren critics have seized on the issue, noting that it - like with the outcry Warren faced for taking a DNA test last year to try to prove her past claims of Native American heritage - shows she's willing to exaggerate her personal story and isn't the candidate she claims to be.

"Sen. Warren is flirting with front-runner status in the Democratic primary, and with front-runner status comes a higher level of scrutiny," said Michael Steel, who was an adviser to former Republican House Speaker John Boehner and to Jeb Bush's 2016 presidential campaign. "She cannot afford the appearance that she is deceitful or inauthentic - and this could feed those narratives."

In an interview Monday with CBS, Warren called being fired for being visibly pregnant "an accurate description" of what occurred. She added that being elected to the Senate in 2012 caused her to "open up" more about her past, revealing new details.

On Tuesday, she offered further affirmation, tweeting: "When I was 22 and finishing my first year of teaching, I had an experience millions of women will recognize. By June I was visibly pregnant - and the principal told me the job I'd already been promised for the next year would go to someone else."

She added via tweet: "This was 1971, years before Congress outlawed pregnancy discrimination - but we know it still happens in subtle and not-so-subtle ways."