Factors that increase the risk of cervical cell changes (dysplasia) that can cause an abnormal Pap test include:

• Being infected with certain high-risk types of the human papillomavirus (HPV).
• Being infected with the human immunodeficiency virus (HIV).
• Smoking or having a history of smoking.
• Sexual intercourse with a partner who is infected with HPV.
• Starting sexual intercourse at an early age (before age 18).
• Having three or more sex partners in a lifetime.
• Having sexual intercourse with someone who has had multiple sex partners.
• Using birth control pills. Studies have shown that women who use birth control pills for many years have an increased risk of cervical cell changes.
• Having an impaired immune system.
• Having multiple full-term pregnancies (high parity).
• Exposure to diethylstilbestrol (DES) in utero, though this is rare.