Sen. Elizabeth Warren's story about being fired early in her career because she was pregnant may sound like an artifact from a less enlightened era, but pregnancy discrimination is alive and well today.

A conservative political website disputed Warren's claim recently after it found public meeting minutes that appeared to contradict Warren's account. The site also noted that Warren's story about leaving her teaching job has changed over the years. But Warren -- a Democrat from Massachusetts who's vying for the Democratic nomination -- stuck by her claim in an interview with CBS News. She then urged other women to share their stories of pregnancy discrimination on Twitter TWTR, +2.07%.

"This was 1971, years before Congress outlawed pregnancy discrimination -- but we know it still happens in subtle and not-so-subtle ways," she wrote.

Indeed, the Pregnancy Discrimination Act passed in 1978, but more than 40 years later, discrimination against pregnant workers is still "incredibly common," said Alex Baptiste, policy counsel at the National Partnership for Women & Families. The U.S. Equal Employment Opportunity Commission fielded more than 2,000 complaints of pregnancy discrimination in 2018.

"It impacts people across industry, pay scale, race, ethnicity, background -- it can happen in any work environment and in any state," Baptiste said.

Some of the country's biggest employers, including Walmart and UPS, have run afoul of pregnancy discrimination laws, and a 2018 New York Times investigation explored its presence across sectors, from financial firms to factory floors.

Pregnancy discrimination can be as overt as an employer firing a worker when they find out she's pregnant, but it also includes less explicit forms of unfair treatment, like not letting a pregnant worker have a water bottle near her work area, Baptiste said. "All of these things have real consequences and affect a pregnant workers employment, earnings and opportunity," she added.