For years, women were told that they needed to get a Pap every year, but now that the necessary annual ritual is no longer deemed as necessary, many women are confused.

The American College of Gynecologists has issued new, very specific guidelines, which are as follows:

• Pap tests should begin at age 21.
• From 21-30, it is fine to get a Pap every two years instead of every year as long as you have had three normal Pap tests in a row and are considered low risk, meaning you have never had moderate or severe dysplasia, cervical cancer, HIV or have a severe medical illness that compromises your immune system.
• After age 30, every three years is fine, but only for women who are low risk.
• After age 70, you can cross scheduling Pap smears off your "to-do" list as long as you have had a normal test for at least 10 years.

There are two main reasons for this change. Most abnormal Paps have minimal potential for progression to cancer. This is particularly true for young women. In the event that a persistent dysplasia is present, the transition from pre-cancerous cells to a true cancer takes not weeks or months, but years.

This doesn't mean that you only need to see your gynecologist once every three years. Even if you're not due for a Pap, you still need to have a breast exam, STD screen, and a pelvic exam to check your uterus and ovaries. And even if you don’t need to have cells sampled from the cervix, your gynecologist will still want to do a basic exam to make sure the cervix and vagina look healthy.

It's important to keep in mind that Pap smears don’t detect 100% of abnormalities. I once biopsied a suspicious growth on a patient's cervix that turned out to be an early cancer. Her Pap smear the year before was read as normal, and had she not come in for her annual exam, I would not have had the opportunity to detect the growth.

Lauren Streicher, M.D., is an Assistant Clinical Professor of Obstetrics and Gynecology at the Feinberg School of Medicine at Northwestern University in Chicago.

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