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Cervical cancer - Causes

Almost all cases of cervical cancer are caused by the human papillomavirus (HPV).


HPV is the name for a very common group of viruses.

You can get it from any kind of sexual contact of the genital area, not just penetrative sex.

Sexual contact includes:

  • vaginal, oral or anal sex
  • any skin-to-skin contact of the genital area
  • sharing sex toys

There are about 100 different types of HPV. Some types are a high-risk for causing cervical cancer.

Two of the high-risk types 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 and people with a cervix who have HPV do not develop cervical cancer.

Read more about HPV

Abnormal cervical cells

HPV can cause cells in the cervix to change.

These abnormal cell changes can develop into cervical cancer over time. Abnormal cells are often called pre-cancerous cells.

It usually takes 10 to 15 years for abnormal cells to become cancer. But in rare cases it can develop quicker. Never ignore symptoms. Always attend cervical screening when it’s due. Regular screening can help prevent cancer from developing.

Abnormal cells are not cancer. But if they are not checked and treated, they can develop into cancer.

Even if you have abnormal cells, the chances of them turning into cervical cancer is very small.

If the changes are found during cervical screening, treatment is highly successful.

Low-grade abnormal cells will even sometimes go back to normal if left untreated.

Other risk factors

HPV infection is very common. But cervical cancer is relatively uncommon.

This suggests that only a very small amount of women are vulnerable to the effects of a HPV infection.

Other risk factors may affect a woman's chance of developing cervical cancer.

Other risk factors include:

  • smoking
  • having a weakened immune system
  • being sexually active in early teenage years
  • if your birth mother took the hormonal drug diethylstilbestrol (DES) while pregnant with you. Talk to your GP about the risks


Women who smoke are twice as likely to develop cervical cancer than those who do not smoke.

This may be because of the harmful effects of chemicals found in tobacco.

Organ transplant or HIV

If you have had an organ transplant or the HIV infection, you are at higher risk of cervical cancer.

You will need to have a cervical screening test more often if you have:

  • had an organ transplant
  • HIV

Tell CervicalCheck and your GP about your condition.

Childbirth and cervical cancer

The link between cervical cancer and childbirth is unclear. In general, having a baby does not put you at any greater risk.

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 30 December 2019
Next review due: 30 December 2022

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.