The new guidelines also say routine Pap screening should begin at age 21. Previously, ACOG urged a first Pap either within three years of first sexual intercourse or at age 21.

The new guidelines say a woman over age 30 with a history of normal pap smears can be screened every three years, and can stop when she reaches age 65 or 70.

"We'll still be able to detect it in a timely fashion, yet put women, particularly young women, at less risk,” said Dr. Cheryl Iglestia of the American College of OBGYNs committee that wrote the new guidelines.

There’s a one in a million chance of developing cervical cancer before age 21, yet teenagers are often screened and treated for abnormalities that experts ay would clear up on their own.

"These patients, based on the fact that they've had minimally abnormal pap smears, wind up getting part of their cervix removed or destroyed and that weakens the cervix causing problems with future pregnancies,” said cancer specialist Dr. Howard Jones of Vanderbilt University.

Pap smears can spot pre-cancerous changes in the cervix in time to prevent invasive cancer. Widespread use has halved cervical cancer rates in the U.S. in recent decades.

The change comes amid a completely separate debate over when regular mammograms to detect breast cancer should begin. ACOG says the timing is a coincidence.

"Since we feel this is not going to change our ability to screen for cancer, I think we're all in agreement of this recommendation change,” said Jones.

The American Cancer Society opposed the mammogram recommendation but supports this one on pap smears. Doctors still urge women to get an annual exam every year.

The recommendations are published in the journal Obstetrics & Gynecology.