The cervix is part of a womans reproductive system. It makes mucus that helps sperm move from the vagina into the uterus or keeps sperm from entering the uterus. Every month during your menstrual period blood flows from the uterus through the cervix into the vagina. During pregnancy, the cervix is closed to keep the baby inside the uterus. During childbirth, the cervix opens (dilates) so that the baby can pass through the vagina.

Before cervical cancer develops, the cells of the cervix start to change and become abnormal. These abnormal cells are precancerous, meaning that they are not cancer. Precancerous changes to the cervix are called dysplasia of the cervix (or cervical dysplasia).

Dysplasia of the cervix is not cancer. It is a common precancerous change that can develop into cancer if it isnt treated. It is important to know that most women with dysplasia do not develop cancer.

Most women have regular cervical screening with a smear test or liquid-based cytology. The screening is designed to find early changes in the cells of the cervix, so that treatment can be given to prevent a cancer from developing. Although the aim of cervical screening is to prevent cancer, it can also sometimes detect a cancer that has already developed, before any symptoms occur.

Cancer of the cervix can take many years to develop. Before it does, changes occur in the cells of the cervix. These abnormal cells are not cancerous, and are called cervical intra-epithelial neoplasia (CIN). Some doctors call these changes pre-cancerous. This means that the cells might develop into cancer in some women if they are not treated. It is important to know that most women with CIN do not develop cancer.

CIN is usually the result of a virus infection: the human papillomavirus (HPV). HPV is a very common virus that can affect the cells of the cervix. It is mainly passed on during sexual intercourse. Most women who have had sexual intercourse will have the virus at some time in their life. However, in many women their immune system will get rid of the virus and they won't even know they had it.

Recently several research trials have looked at using vaccines to prevent HPV infection. The results seem to show that in future, it will be possible to vaccinate young women against the high-risk types of HPV and so prevent most cases of cervical cancer.

CIN that might develop into cancer can be treated in various ways. The aim of any treatment is to remove or destroy all of the affected cells. This can be done using surgery, where the affected area of the cervix is removed by large loop excision (LLETZ) or cone biopsy. Instead, the affected areas can be destroyed by laser therapy, or using heat (cold coagulation). These procedures are usually carried out in an outpatient clinic and may be done by doctors or specialist nurses.