You asked, we answered: What causes an abnormal Pap smear?

Woman at computer



My pap smear came back abnormal, but my biopsy was not concerning. What could be the cause of the abnormal results? This isn't the first abnormal reading for me.

Answered by OB-GYN Karen Carlson, MD:

The Pap smear is a screening test that looks for cervical cancer. It is not diagnostic. In other words, an abnormal Pap smear just tells us that more testing or more frequent Pap smears need to be done. Having an abnormal Pap smear does not mean you have cancer or even precancerous cells of the cervix. Most abnormal Pap smear results will not progress to cancer, and abnormal cells can usually be treated when identified early, to prevent cervical cancer. 

Most abnormal Pap smears are caused by certain types of human papillomavirus, or HPV. Frequently, these viruses and the cell changes that they cause on the cervix will go away on their own. However, HPV may stay in the body for many years without causing any signs or symptoms. 

When an abnormal Pap smear is concerning, you may need to have a biopsy of the cervix, which is usually done through a procedure called a colposcopy. This is done in the office and usually, a tissue biopsy is sent for pathology. This will tell the actual diagnosis as to what the abnormality is on the cervix. Based on the biopsy results, you may need to have treatment to remove the abnormal cells. Treatment is usually recommended if the cervical abnormality is considered precancerous. However, if the abnormality is just mild or even moderate, it may be better to continue close observation versus having a procedure to treat the abnormality. Your provider will be able to decide if treatment is necessary, based on the biopsy results from the cervix.

Roughly four out of every 10 women who need to have a colposcopy will have a normal result or a result that does not need any immediate treatment. You may be advised to continue with Pap smears for the prevention of cervical cancer. This decision will be based on your age and your desire for childbearing, in addition to the results of the colposcopy.

HPV is very prevalent. Roughly 79 million people in the US are diagnosed with HPV currently. HPV is spread through skin-to-skin contact, usually through having vaginal, anal, or oral sex. In most cases, your body is able to fight off the HPV over one to two years, and the virus will go away without causing any problems. Having the Gardasil (HPV) vaccinations, if not already completed, may help clear the virus. Gardasil is now approved and indicated for women through age 45, to help prevent not only cervical, but vulvar, vaginal, anal and head and neck cancers that are caused by HPV.

Going back to the original question, mildly abnormal cervical cells may not be concerning and may not need treatment. The abnormality may resolve on its own. However, repeat Pap smear testing on a yearly basis for several years may be recommended to monitor the condition and check for either resolution, which commonly is seen, or worsening of the abnormality, which may need treatment in order to prevent cervical cancer.