Cervical screening aims to prevent cervical cancer from developing. Find out more about the screening programme and how you have the test.

What is screening?

Screening means testing people for early stages of a disease before they have any symptoms. For screening to be useful the tests:

• need to be reliable at picking up cancers or abnormalities that could lead to cancer
• overall must do more good than harm to people taking part
• must be something that people are willing to do

Screening tests are not perfect and have some risks. The screening programme should also be good value for money for the NHS.

What is cervical screening?

Cervical screening is a way of preventing cancer. This is either by:

• finding and treating abnormal cell changes in the neck of the womb (cervix), these changes could lead to cancer if left untreated
• testing for the human papilloma virus (HPV)

Screening to look for changes in cervical cells uses a test called cytology, which many people may know as the smear test. A nurse or doctor takes a sample of cells from the cervix with a small brush. They send the sample to a laboratory to check for abnormalities.

The HPV test is carried out in the same way as checking the cells, so if you have had cervical screening before you won't notice any difference.

Currently in most of the UK you have a 'smear' test first and you might have a HPV test after if there are changes to help decide what should happen next. This is changing so that you have a HPV test first. If you have HPV they will then check for changes in the cells. Having a test for HPV first is called primary HPV testing. 

HPV testing (primary HPV testing)

HPV stands for human papilloma virus. There are different types of HPV. Some types can cause cervical cells to change (become abnormal). These types are called high-risk HPV.  Research has shown that most cases of cervical cancer are linked to high-risk HPV.

Research has shown that testing for HPV is a more accurate way of finding people at risk of developing changes. So now the national screening programmes in the UK are introducing the HPV test as the first test you have. They only check for abnormal cells if you have HPV. You might hear this called primary HPV testing or HPV primary screening.  

If you live in Wales you will have primary HPV testing as your screening test. The rest of the UK is rolling it out over the next couple of years.  

How you have the cervical screening test

To have the test you take off your underwear and lie on your back on a couch. You need to lie with your knees drawn up and spread apart. If this position is difficult for you, you can ask your doctor or nurse to take the cell sample when you are lying on your side with your knees drawn up.

To take the sample of cells, your doctor or nurse gently slides an instrument called a speculum into your vagina so that they can see the cervix clearly. Having the speculum put in may be a little uncomfortable, but it shouldn't hurt. It can be more uncomfortable if you are very tense. Try to relax. Taking a few deep breaths can help. 

Your doctor or nurse gently scrapes the surface of your cervix with a small soft brush. This collects a sample of cells from the outer layer of the cervix. They put the sample into a pot of liquid and send it to the laboratory. Then they take out the speculum and the test is over. You can get down from the couch.

In the laboratory, a pathologist looks at the sample under a microscope. They examine the cells and report any abnormal ones. They may also test to see if HPV is in the sample. They might test for HPV first and only check for abnormal cells if you have HPV. 

After the cervical screening test

You usually get the results within 2 to 6 weeks. Ask your doctor or nurse when you have the test how long to expect to wait for the results.

This video shows you what happens, it lasts 1 minute 27 seconds. 

Who has cervical screening?

The NHS cervical screening programme invites women from ages 25 to 64 for cervical screening. Women aged 25 to 49 are invited every 3 years. After that, women are invited every 5 years until the age of 64.

You need to be registered with a GP to get your screening invitations.

Cervical screening also applies to other people within this age range who have a cervix, such as trans men. You can talk to your GP about this.

Why younger women don't have screening

We know from research that cervical cancer is very rare in women younger than 25. Changes in the cells of the cervix are quite common in this age group. These changes often return to normal and are less likely to develop into cancer. So screening them leads to unnecessary treatment and worry.

Scientists have worked out that screening younger women leads to more harms than benefits.

Screening results

There are several different results that you might have after a cervical screening test. Most women have a normal result.

Benefits of cervical screening

Research shows that cervical screening prevents at least 2,000 cervical cancer deaths each year in the UK.

Women screened between the ages of 35 to 64 are thought to have a 60 to 80% lower risk of being diagnosed with cervical cancer in the 5 years following the test compared to women who haven't been screened. The benefit of screening increases with age.

Since cervical screening started in the 1980s in Great Britain, rates of cervical cancer have almost halved.

Possible harms of cervical screening

Cervical screening works very well but, like any screening test, it isn’t perfect. In a few cases, tests will seem to find abnormal changes that aren’t really there. This is called a false positive result. It leads to unnecessary worry for the woman and also the need for more tests. 

There is also a risk that cell changes may be missed. This is called a false negative result. So it is important to go for screening every time you are invited.

Sometimes it is difficult to tell whether changes in the cervix will go back to normal or will develop into cancer after some years. So, some women will have treatment for changes to cervical cells that would not have caused any harm if they had been left alone. This is called overdiagnosis or overtreatment. 

For a few women, the treatments may cause problems such as bleeding afterwards or a small increase in future pregnancies of having the baby early.

It is hard to know exactly how often women are overdiagnosed or overtreated in this way. But in women from their early 20s to mid 60s, the benefits of preventing cervical cancers are very great.

HPV vaccination

Since 2008, girls aged 12 and 13 have been offered a vaccination against the human papillomavirus (HPV). The vaccine can prevent over 70% of cervical cancers.

It is important for girls to have the vaccination when it is offered at school. But there are many types of HPV linked to cervical cancer. Although the vaccine protects against the 2 types that cause most cases of cervical cancer, it doesn't protect against all of them. This means that screening is still important for girls who have been vaccinated.

If you have symptoms

As well as attending for screening when you are invited, you still need to look out for any unusual changes to your body. Check for:

• abnormal bleeding (such as bleeding between periods)
• vaginal discharge that smells unpleasant
• pain during sex

See your doctor if you notice anything unusual. There are many conditions that can cause these symptoms. Most of them are much more common than cervical cancer. But it is important to get your symptoms checked out.