WASHINGTON — Pregnant women have new protections against on-the-job discrimination.

The Equal Employment Opportunity Commission has updated 30-year-old guidelines to make clear that any form of workplace discrimination or harassment against pregnant workers by employers is a form of sex discrimination and illegal.

“Despite much progress, we continue to see a significant number of charges alleging pregnancy discrimination, and our investigations have revealed the persistence of overt pregnancy discrimination, as well as the emergence of more subtle discriminatory practices,” EEOC Chairwoman Jacqueline A. Berrien said in a statement.

The guidelines prohibit employers from forcing pregnant workers to take leave and acknowledge “employers may have to provide light duty for pregnant workers.” After childbirth, lactation is now covered as a pregnancy-related medical condition.

It's not just women who will benefit.

The guidelines say that when it comes to parental leave, “similarly situated” men and women must be treated on the same terms.

The update comes two weeks after the Supreme Court agreed to consider a case involving the EEOC's duty to try to settle charges of job discrimination before filing lawsuits against employers.

The issue has gained increasing attention and has vexed business groups as the Obama administration ratchets up its enforcement of the nation's anti-discrimination laws.

The latest EEOC data shows a 46 percent increase in pregnancy-related complaints to the EEOC from 1997 to 2011.

In its report, the agency cites specific, real-life examples of what it considers illegal discrimination.