Having cancer tests while pregnant
If your GP or pregnancy doctor thinks there may be a link between your symptoms and cancer, they will refer you to a hospital specialist. Tests to diagnose cancer can usually be done without harming the baby.
Tests for cancer during pregnancy
If your GP or pregnancy doctor (obstetrician) thinks there may be a link between your symptoms and cancer, they will refer you to a hospital specialist. The specialist you will meet depends on the symptoms you have. After the specialist has examined you, they will talk to you about the tests you need.
Making sure you are well is the most important thing for having a healthy baby. But it is important to find the cause of your symptoms.
You may worry that tests could put the baby’s health at risk. Tests to diagnose cancer can usually be done without harming the baby. Your doctors will choose tests that do not risk exposing the baby to harmful amounts of radiation. They will try to avoid:
If your doctors think you need a test they would usually avoid, they will talk to you about it. They will explain how they can reduce any possible risk to the baby.
If you have had tests and later find you are pregnant, talk to your doctors. With most tests there is no risk to the baby. If there is a risk, it is a very small risk.
Ultrasound scans
An ultrasound scan uses sound waves to build up a picture of the inside your body. You may have already had an ultrasound during your pregnancy to check the baby’s development. There is no risk to the baby.
You can usually have an ultrasound on most parts of the body. Where you have it depends on your symptoms. For example:
- if you have vaginal bleeding, you may have an ultrasound of your pelvis (the lower tummy area between your hips)
- if you have breast symptoms, you may have an ultrasound of your breast and armpit
- if you have digestive symptoms, you may have an ultrasound of the tummy or liver in the upper tummy area.
X-rays
X-rays are used to take pictures of the inside of your body. Having an x-ray is not painful and only takes a few minutes.
You can have x-rays if the baby is not directly exposed to the rays. For example, you can have x-rays of your head, chest, arms and legs. The person taking the x-ray (radiographer) will place a lead shield over your tummy to protect the baby. Doctors sometimes call this pelvic shielding.
MRI scan
An MRI scan uses magnetism to build up a detailed picture of areas of the body. An MRI does not use x-rays, but you have it in the x-ray department of a hospital. The person who does the scan is a radiographer. They may give you an injection of a dye called a contrast. This helps show certain areas of the body more clearly. The dye may pass through the placenta. This may be harmful to the baby during the first trimester of pregnancy (the first 13 weeks or 3 months). For this reason, doctors try to avoid MRI scans during the first trimester.
Biopsy
A biopsy is when doctors remove a small piece of tissue or a sample of cells from an area of the body. This is then sent to be checked under a microscope. This is how doctors find out whether an abnormal area or lump (tumour) is cancerous (malignant) or non-cancerous (benign).
You may need a biopsy to:
- check a lump
- remove a lymph node (gland)
- remove a mole or freckle on the skin.
Most biopsies in pregnancy use a local anaesthetic to numb the area. It is safe to have a local anaesthetic during pregnancy.
If you cannot have a biopsy using a local anaesthetic, you may need to have a general anaesthetic. If the pregnancy is at an early stage, your doctor may recommend waiting to have the biopsy until you are in the second trimester (over 14 weeks pregnant).
Bone marrow biopsy
Bone marrow is spongy material found in your bones. For a bone marrow biopsy, a small sample of bone marrow is taken from the back of the hip bone (pelvis). Rarely, the sample is taken from the breastbone (sternum). The sample is checked by a doctor who specialises in studying blood cells (haematologist).
This test is safe during pregnancy.
Colposcopy and biopsy
This test uses a microscope called a colposcope to look closely at your cervix. The cervix is at the entrance to the womb.
It is safe to have a colposcopy while you are pregnant. The doctor or nurse will usually take a small sample of cells (a biopsy) from the cervix. They will send this to a laboratory to check for cancer cells.
You may have this test if you had a cervical screening test before you were pregnant and it showed abnormal cells on the cervix.
You may have a cervical screening test if you have vaginal bleeding during pregnancy and other possible causes have been ruled out.
You will only have a biopsy of this area if it is necessary. If you are further along in your pregnancy, your specialist may recommend having the biopsy after the baby is born.
There is more risk of bleeding during this type of biopsy in pregnancy. Your doctors may do the biopsy in an operating theatre. They may recommend you have it under a general anaesthetic. They may also recommend waiting until the second trimester to have a general anaesthetic. This is because having a general anaesthetic in the first trimester can slightly increase the risk of miscarriage.
Surgery during the second or third trimester can increase the risk of going into labour early or having a late miscarriage. You may be offered drugs to reduce the risk of you having contractions and going into labour.
Waiting for test results
Waiting for test results can be a difficult time. It may take from a few days to a couple of weeks for the results of your tests to be ready. You may find it helpful to talk with your partner, your family or a close friend. Your specialist nurse, Mummy’s Star or other cancer support organisations can also help.
You may find it helpful to talk to one of our cancer information nurse specialists on 0808 808 00 00.
Related pages
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
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References
Below is a sample of the sources used in our pregnancy and cancer information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
de Haan J, Verheecke M, et al. Oncological management and obstetric and neonatal outcomes for women diagnosed with cancer during pregnancy: a 20-year international cohort study of 1170 patients. Lancet Oncology. 2018. Vol 19 [accessed October 2023]
Public Health England, Cancer before, during and after pregnancy, National Cancer Registration and Analysis Service 2018 [accessed October 2023]
Silverstein J, Post AL, Chien AJ, Olin R, Tsai KK, Ngo Z, Van Loon K. Multidisciplinary management of cancer during pregnancy. JCO Oncol Pract. 2020 Sep;16(9):545-557. doi: 10.1200/OP.20.00077. PMID: 32910882. [accessed September 2023]
Wolters V, Heimovaara J, Maggen C, et al. Management of pregnancy in cancer Int J Gynecol Cancer 2021;31:314–322.
Reviewer
Consultant Medical Oncologist & Honorary Associate Professor
Date reviewed
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