Washington ? Women can delay having their first Pap test for cervical cancer until they turn 21 and many can wait longer to go back for follow-up screenings, according to new guidelines released today by a major medical group.

The American College of Obstetrics and Gynecologists recommended the change after concluding that more frequent testing did not catch significantly more cancers and often resulted in girls and young women experiencing unnecessary stress, anxiety and sometimes harmful treatments because of suspicious growths that would not cause problems.

“We really felt that the downsides of more frequent screening outweighed any benefits,” said Alan Waxman, a professor of obstetrics and gynecology at the University of New Mexico who led the revision of the guidelines. “More testing is not always more intelligent testing.”