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Pregnancy and abnormal cervical cells

Find out about abnormal cervical cells and pregnancy. 

Cervical screening during pregnancy

You might find the following information helpful, but it is best to talk to your own doctor, who is in the best position to answer your questions.

The NHS cervical screening programme recommends that in most cases women should not have cervical screening tests if they are, or could be, pregnant. Pregnancy can make the result of the test harder to interpret and it is likely to be inaccurate.

Planning to become pregnant

If you are planning to become pregnant, it is a good idea to check with your GP that you are up to date with your cervical screening. Then you can have the test and any treatment necessary before you become pregnant.

Already pregnant 

If you are already pregnant, and are due to have a cervical screening test, you can usually wait to be screened until 3 months after your baby is born. When you are invited for your test, you should let your GP or clinic know that you are pregnant. They will postpone the test until after the baby is born.

If you have previously had an abnormal result from a cervical screening test, you may need to have another screening test while you are pregnant. Your GP or midwife may ask you to have the test at your first antenatal appointment. This test will not interfere with your pregnancy. If the results come back abnormal, or if a test you had just before you became pregnant shows abnormal results, you don't need to worry.

This doesn't mean that you have cancer, but that there are some abnormal cells that can be easily treated a few months after the birth.

You may need to have a colposcopy (a close examination of your cervix and vagina). This examination is safe to have during pregnancy, and your doctor can see how much the cells on your cervix have changed.

Treatment for abnormal cells during pregnancy

Remember that if your doctor tells you that you have abnormal cells or CIN 1, 2 or 3, you don't have cervical cancer. You have a pre cancerous condition that can easily be treated.

Before giving birth

If you only have mild changes to the cells on your cervix (CIN 1), you will not need to have any treatment until around 3 months after your baby is born. After that, you may have another colposcopy to check the cervical cells again. In many women with mild changes, they go back to normal without any treatment.

But if the cells are more abnormal (CIN 3), your doctor may ask you to have another colposcopy when you are approximately 6 months pregnant to keep an eye on them. The abnormal cells are not likely to change much over the time of your pregnancy.

If you are pregnant and your colposcopy shows that the CIN has started to turn into an invasive cancer, your doctor will need to take a tissue sample, probably by loop diathermy or LLETZ. But your specialist will not do this unless it is absolutely necessary.

After giving birth

If the cells on your cervix have not gone back to normal after you have given birth, you may then have treatment to remove them. You can discuss your treatment options and any worries you have with your GP and midwife. It is important to make sure that you go to all of your follow up appointments after you have had your baby.

Pregnancy after a cone biopsy

Cone biopsy can cause particular problems. But these are not common.

Cervical stenosis

Firstly there is a very, very small chance that the cervix can become so tightly closed after cone biopsy that sperm cannot get in at all. This is called cervical stenosis. If this happened, you would not be able to get pregnant naturally. If you are having periods after a cone biopsy you have not got complete cervical stenosis. If the lining of the womb can get out, when it is shed as a period, then sperm can get in.

Future pregnancies

Some treatments for CIN or stage 1A cervical cancer can lead to a small risk of complications in future pregnancies. Women who have had a cone biopsy have:

  • a higher chance of their babies being born before 37 weeks (preterm delivery)
  • a higher risk of a baby that weighs less than 2.5kg (low birthweight)
  • an increase in birth by Caesarean section
  • an increased risk of early birth

You may have an increased risk of early birth because the cone biopsy has weakened your cervix. The cervix is really a muscle that keeps the entrance to the womb closed unless you are in labour.

In some women who have had a cone biopsy, there is a risk that the cervix may start to open too soon because of the weight of the growing baby. Serious problems can usually be prevented.

If your doctor thinks your cervix may start to open too soon, you can have a sort of running stitch put around it to hold it shut. Your doctor may call this a purse string suture. The stitch is cut before you go into labour, usually at about week 37 of your pregnancy. The cervix can then open normally for the baby to come out.

Some people have reported labour being longer in women who have had cone biopsy because the cervix takes longer to open. But this has not been confirmed by research.

Pregnancy after other treatment

It is very unlikely that any other treatment for abnormal cells, such as laser therapy, diathermy, cold coagulation or cryotherapy will affect your ability to get pregnant in the future. 

The most likely way that treatment for abnormal cervical cells can affect your ability to get pregnant, is if you get a infection after you are treated which spreads into your fallopian tubes. Infection in the fallopian tubes can cause them to become blocked. If both your tubes are blocked, then you cannot get pregnant because your eggs cannot travel down the tubes into the womb.

Such a severe infection is unlikely after treatment for an abnormal smear. If you do have any symptoms of infection after treatment, go straight back to your doctors. You may need antibiotics to clear the problem up before the infection can spread and do any damage. These symptoms include:

  • heavy bleeding, especially if more than during your period
  • a vaginal discharge that smells or is green or yellow in colour
  • period like pains that last more than a day or two
  • fever

LLETZ

As with cone biopsy, studies looking at LLETZ (large loop excision of the transformation zone) show that there is a small rise in risk of birth before 37 weeks and having a low birthweight baby.

This risk may depend on the amount of cervical tissue that has been removed. There is also a slight increase in the risk of waters breaking early (premature rupture of membranes) for women who have had LLETZ.

You should let your health care team know you have had this procedure, if you are pregnant or trying to become pregnant.

What to remember

You may feel worried about these risks, but remember:

  • the risk of developing serious side effects during pregnancy is small
  • if you have cervical abnormalities, having the necessary treatment is very important
  • your doctor will talk through the treatment options, and discuss any potential risks to future pregnancies

Contraception

It is safe to use contraception while having a cervical screening test.

Last reviewed: 
26 Jun 2017
  • The risk of preterm birth following treatment for precancerous changes in the cervix: a systematic review and meta-analysis
    F Bruinsma and M Quinn
    An International Journal of Obstetrics and Gynaecology(BJOG). 2011 Aug;118(9):1031-41

    • Risk of preterm birth after treatment for cervical intraepithelial neoplasia among women attending colposcopy in England: retrospective-prospective cohort study
      A Castanon and others
      British Medical Journal (BMJ). 2012 Aug 16;345:e5174

    • Obstetric outcomes after conservative treatment for intraepithelial or early invasive cervical lesions: systematic review and meta-analysis
      M Kyrgiou and others
      Lancet. 2006 Feb 11;367(9509):489-98

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