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Although all of the exact causes of cervical cancer are not known, there are certain risk factors that may increase a woman’s likelihood of developing this disease.

The most significant risk factor for cancer of the cervix is infection with human papillomavirus (HPV). HPVs are a collection of more than 100 types of viruses that can cause noncancerous tumors (masses of excess tissue) called papillomas (warts). HPV infection is common among women and men throughout the world.

Data from The National Health and Nutrition Examination Survey (NHANES) published in February 2007 provided the first national estimate of the prevalence of HPV infection among women in the United States. Researchers found that nearly 27 percent of women between the ages of 14 and 59 tested positive for one or more strains of HPV. The prevalence was highest in women 20 to 24 years of age.

Different types of HPV affect different regions of the body. For example, warts that appear around the male and female genitals are a form of HPV commonly known as genital warts. This infection is transmitted during skin-to-skin sexual contact, including vaginal and anal intercourse and oral sex. Genital warts do not typically lead to cervical cancer, and therefore, this type of HPV is labeled low risk.

However, other high-risk forms of HPV can cause cervical cancer. Two strains in particular (HPV-16 and HPV-18) account for about two-thirds of cervical cancers, according to the American Cancer Society (ACS). Other "high risk" strains of HPV include HPV 31, HPV 33 and HPV 45. In most cases, the infection produces no symptoms and clears spontaneously because of the immune system’s response to the virus. Not all of the women infected by HPV will develop cervical cancer, but HPV-16 and HPV-18 infection place women at greater risk for developing cervical cancer.

These viruses are also a major cause of penile cancer, a rare cancer that occurs in men. Health officials emphasize that use of condoms prevent transmission of HPV only in the areas of the penis covered by the condom. Condom use does not prevent transmission of the virus in the uncovered areas. In 2006, the U.S. Food and Drug Administration (FDA) approved an HPV vaccine, which protects women against four strains of the virus, including HPV-16 and HPV-18. The vaccine is most effective on women who have not been previously exposed to HPV.

Women can reduce their risk of becoming infected with HPV by:

• Getting vaccinated against HPV if their physician indicates they are a good candidate for the vaccine
• Refraining from sexual activity at an early age
• Limiting their number of sexual partners
• Avoiding sex with men who have had multiple partners
• Using condoms consistently every time they have sex

Other conditions are also risk factors for cervical cancer. These include:

• Human immunodeficiency virus (HIV) infection. HIV is the virus that causes AIDS (acquired immune deficiency syndrome). Women with HIV have compromised immune systems and therefore are more likely to contract HPV, which may lead to cervical cancer. Scientists believe that a patient’s immune system plays a vital role in eliminating and slowing the progression of cancer cells. Therefore, cervical cancer in patients with HIV may become invasive more quickly than in patients with healthy immune function.
  
  
• Chlamydia infection. Chlamydia is one of the most common sexually transmitted diseases in the United States. This bacterial infection is spread through sexual contact, and many women do not realize that they have become infected because they experience no symptoms. Recent studies of blood tests suggest that women with past or current chlamydia infection are at greater risk of developing cervical cancer than women who have never had chlamydia. Further studies are needed to support this finding.
  
  
• Diethylstilbestrol (DES). DES is a hormonal drug that was prescribed from 1940 to 1971 to reduce the risk of miscarriages in some women. One daughter of every 1,000 mothers who took DES during pregnancy develops cancer of the vagina or cervix. The incidence of these cases of cervical cancer appears to be falling. Most DES-exposed women who developed cervical cancer developed it at a young age and the youngest women exposed to this drug in utero are now in their late 30s.

Additional risk factors of cervical cancer include:

• Smoking
• Excess body weight
• Diet low in fruits and vegetables
• Family history of cervical cancer
• Having  multiple full-term pregnancies
• Low socioeconomic status (which is often accompanied by poor access to healthcare and fewer screenings for the disease)