Decorative image

Pregnancy and abnormal cervical cells

Find out about cervical screening during pregnancy, what happens if you have abnormal cells when you’re pregnant, and pregnancy after treatment for abnormal cells.

Cervical screening during pregnancy

The NHS cervical screening programme say that routine cervical screening tests can usually be delayed in pregnant women until after they have had their baby. Pregnancy can make the result of the test harder to interpret and could be inaccurate.

Planning to become pregnant

If you're planning to become pregnant, it's 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 if you need treatment you can have it 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 have the test 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 can then delay the test.

If you've previously had an abnormal result from a cervical screening test, or you haven't had a screening test in the last 3 to 5 years, you may need to have a screening test while you are pregnant. Your GP or midwife might ask you to have the test at your first antenatal appointment. This test is safe to have when you are pregnant.

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) while you are pregnant. This 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 cervical cells (or CIN 1, 2 or 3), you don't have cervical cancer. Some of the abnormal cells could eventually turn into cancer if left untreated.

Before giving birth

If you only have mild changes to the cells on your cervix (CIN 1), you won't 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.

If the cells are more abnormal (CIN 2 or 3), your doctor may ask you to have another colposcopy when you are about 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 cell changes have started to turn into cancer, your doctor will need to take a tissue sample. This is probably by a procedure called LLETZ (large loop excision of the transformation zone). But your specialist will not do this unless it's 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 or midwife, or your doctor or specialist nurse at the colposcopy clinic.

It's important to make sure that you go to all of your follow up appointments after you've had your baby.

Pregnancy after a cone biopsy

A cone biopsy removes a cone shaped wedge of tissue from your cervix. It can cause particular problems with future pregnancies. But these are not common.

Narrowing of the cervix

After a cone biopsy there is a very small chance that the cervix can narrow. This is called cervical stenosis. The cervix might become so tightly closed that sperm can't get in. If this happened, you wouldn't be able to get pregnant naturally.

If you're 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.

Some women may need surgery to stretch (dilate) the cervical opening.

Future pregnancies

Some treatments for CIN or very early stage cancer (stage 1A) 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

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.

Pregnancy after other treatment

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

The most likely way that these treatments can affect your ability to get pregnant, is if you get an infection after treatment which spreads into your fallopian tubes.

Infection in the fallopian tubes can cause them to become blocked. If both your tubes are blocked, then your eggs can't travel down the tubes into your womb. This would mean that you couldn't get pregnant naturally.

Such a severe infection is unlikely after treatment for abnormal cells. See your GP straight away if you have any symptoms of infection. These can include:

  • heavy bleeding, especially if it's more than during a period
  • a vaginal discharge that smells or is green or yellow in colour
  • period like pains that last more than a day or two
  • a high temperature (fever)

LLETZ

As with cone biopsy, studies looking at pregnancy after LLETZ show that there is a small rise in risk of birth before 37 weeks and having a low birth weight baby. This risk can depend on the amount of cervical tissue that has been removed.

There is also a slight increase in the risk of your waters breaking early (premature rupture of membranes) if you've had treatment with LLETZ.

If you are pregnant, you should let your midwife or doctor know if you have had treatment for abnormal cervical cells.

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 treatment is very important
  • your doctor will talk through the treatment options, and discuss any potential risks to future pregnancies
Last reviewed: 
26 Jun 2017
  • NHS Cervical Screening Programme: Colposcopy and Programme Management, 3rd edition
    Public Health England, 2016

  • Adverse obstetric outcomes after local treatment for cervical pre invasive and early invasive disease according to cone depth: systematic review and meta analysis
    M Kyrgiou and others
    BMJ, 2016. Volume 354, Issue 3633

  • The risk of preterm birth following treatment for precancerous changes in the cervix: a systematic review and meta-analysis
    F Bruinsma and M Quinn
    BJOG: An International Journal of Obstetrics and Gynaecology, 2011. Volume 118, Issue 9

    • Risk of preterm birth after treatment for cervical intraepithelial neoplasia among women attending colposcopy in England: retrospective-prospective cohort study
      A Castanon and others
      BMJ, 2012. Volume 345, Issue 5174

    Information and help

    Dangoor sponsorship

    About Cancer generously supported by Dangoor Education since 2010.