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What causes abnormal cells in the cervix

1. Why you are offered a free cervical screening test
2. What causes abnormal cells in the cervix
3. Cervical cancer
4. Benefits and limitations of screening
5. The CervicalCheck screening programme


Abnormal cells in the cervix can lead to cervical cancer.

Abnormal cells are sometimes called pre-cancerous cells.

They are generally caused by types of human papillomavirus (HPV).

HPV is a very common virus. Most people will have had it at some time in their lives. HPV is the main cause of cervical cancer.

It is spread by skin-to-skin contact during sexual activity. This can include vaginal or anal sex. It can also be spread through oral sex or other close skin-to-skin touching during sex.

Women who have sex with women can spread the virus regardless of their history with men.

If you have ever engaged in any sexual activity, you were probably exposed to HPV. Fortunately, almost all of these infections will have been cleared by the immune system without the person even knowing they had HPV. 

You or your partner could have HPV without knowing it. This is because HPV can be present in your body for years with no symptoms.

If you have never had sex, your chance of having HPV is low. This does not mean there is no risk of developing cervical cancer, only a very low risk.

If you are not currently sexually-active, but have had partners in the past, you could have HPV. You should continue attending for screening tests.

Types of HPV

There are over 100 different types of HPV.

For most people, the virus goes away on its own and doesn't cause any harm.

But infection with some types of HPV can cause changes in the cells of the cervix. The types of HPV associated with cancer are called 'high-risk' types.

Two of the high-risk types, HPV-16 and HPV-18, cause 7 out of 10 cervical cancers.

Other types of HPV can cause genital warts. These are called 'low-risk' types. Low-risk types do not cause cancer.

Most women who have HPV, even the types that cause changes to the cells of the cervix, do not develop cervical cancer.

Can you prevent HPV?

It can be difficult to prevent HPV. This is one of the reasons why having a screening test when it's due is important.

Using a condom during sex can lower your chances of getting HPV. But, as condoms don't cover the entire genital area, they are not guaranteed to prevent the spread of HPV.

If you smoke, you should stop smoking. Smoking may make it harder for your body to clear HPV.

The free HPV vaccine given to schoolgirls can protect against 2 of the high-risk types of HPV (HPV-16 and HPV-18). But if you have had the vaccine you will still need to have screening tests when they are due. This is because the vaccine does not protect against all high-risk types of HPV.

Having screening tests when they're due means any abnormal changes in the cells of the cervix can be picked up early. The earlier changes are found, the easier they are to treat.

HPV testing

After you have a screening test, your test sample is sent to a laboratory. Two lab scientists will inspect your sample.

If they find low-grade changes in the cells of your cervix, your sample will also be tested for HPV.

If no HPV is found, you will carry on attending screening tests as normal. Your next cervical screening test will be in 3 or 5 years, depending on your age.

If HPV is found, you will need to have an examination called a colposcopy. A colposcopy is a more detailed look at the cervix. It's free of charge. You will have it done in a hospital.

How common are abnormal cells

The majority of cervical screening test results are negative or normal.

In most cases, screening test results do not show that you have abnormal cells. This means that you will be called for your next screening test in 3 or 5 years, depending on your age.

A normal result does not definitely mean that you don't have cancer. This is because cervical screening isn't perfect. You may still be at risk of developing cervical cancer in the future. This is why you should always attend your cervical screening test when it's due.

Learn more about abnormal and normal results.