(HealthDay News) -- Most women should undergo a Pap test and a pelvic exam every year to detect the beginnings of cervical cancer. Any woman aged 21 and older, or any woman under age 21 if she has been sexually active for three years or more, should have a yearly Pap test, the U.S. Department of Health and Human Services says.

Cervical cancer has a high survival rate if caught early. A Pap smear checks for abnormal cells and certain infections that can indicate future trouble.

Human papilloma virus (HPV) causes a common sexually transmitted disease and can also be responsible for cervical cancer if left untreated. But many people have HPV with no apparent symptoms.

You should talk to your doctor about your risks of cervical cancer and HPV, and if you need a Pap smear. Some women, including those who have had a certain type of hysterectomy and some women over age 65, may not need the annual test, the agency says.