Diagnosing cancer in pregnancy

If you have symptoms that your GP or pregnancy doctor (obstetrician) thinks could be cancer, you will be referred to hospital for tests.

Although it’s natural to worry about whether tests could harm the baby, it is important thing is to find out the cause of your symptoms. Tests to diagnose cancer can usually be done without harming the baby. But your doctors will usually try to avoid bone, CT and PET scans.

You may have some of the following tests to diagnose the cancer.

  • Ultrasound scans.
  • X-rays, if they will not expose the baby directly to x-rays. Your doctor may place a lead shield over your tummy to protect the baby.
  • Mammogram (breast x-ray). Again, a shield might be used for this test.
  • MRI (magnetic resonance imaging) scan. This is usually done after the first three months of pregnancy.
  • Biopsy.
  • Bone marrow biopsy.
  • Colposcopy and biopsy.

How the cancer is diagnosed

If you have symptoms that your GP or pregnancy doctor (obstetrician) thinks could be cancer, you will be referred to a hospital specialist for tests.

The type of specialist you see will depend on the symptoms you have. After they have examined you, they will talk to you about the tests you need.

It is important to find out the cause of your symptoms. The most important factor in having a healthy baby is making sure you are well. But it is natural to worry about whether any of the tests could harm the baby.

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 a possibly harmful amount of radiation. They usually try to avoid:

  • bone scans
  • CT (computerised tomography) scans
  • PET (positron emission tomography) scans.

Sometimes your doctors might think it is important for you to have a test that should ideally be avoided in pregnancy. If this happens, they will discuss it with you and explain how they can reduce any risk to the baby.

If you have had tests and later find you are pregnant, talk to your doctor. With most tests, there is no risk to the baby, or if there is it is very small.


Tests you may have

Ultrasound scans

An ultrasound scan uses sound waves, not x-rays, to build a picture of the area being scanned. You may already have had one done during pregnancy to check the baby’s development. There is no risk to the baby.

An ultrasound can be done on most parts of the body depending on your symptoms.

For example:

  • If you have gynaecological symptoms, you may have an ultrasound of your pelvis (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 area.

X-rays

You can usually have x-rays if they will not expose the baby directly to x-rays. This includes the head, chest and arms and legs (limbs). The person taking the x-ray (radiographer) will place a type of lead shield over your tummy to protect the baby. Doctors sometimes call this pelvic shielding.

Mammogram (breast x-ray)

It is safe to have a mammogram to check your breasts during pregnancy. The amount of radiation is very low and will not harm the baby. But the radiologist will still shield  your tummy area to protect the baby.

MRI (magnetic resonance imaging) scan

An MRI scan uses magnetism to build up cross-sectional pictures of your body. It does not use x-rays. Although there is no evidence that MRI scans are a risk to the baby, doctors try to avoid them in the first three months of pregnancy.

People usually have a contrast injection called gadolinium with an MRI scan. It helps give a better picture of the area being scanned. You will not be given this injection because it may pass through the placenta to the baby.

Biopsy

A biopsy is a common test to diagnose cancer. Your doctor takes a small sample of tissue or cells from the area to check for cancer cells.

Most biopsies in pregnancy are done using a local anaesthetic to numb the area. It is safe to have a local anaesthetic during pregnancy. You may have a biopsy to check a lump, or to remove a lymph node or a mole or freckle on the skin.

If a biopsy cannot be done with a local anaesthetic you may need to have a general anaesthetic.

Bone marrow biopsy

A bone marrow biopsy takes a small sample of the bone marrow (where blood cells are made) from inside your bones for testing. The sample is usually taken from your hip bone. It can be done safely during pregnancy.

Colposcopy and biopsy

A colposcopy is a test to examine abnormal cells of the cervix. The cervix is at the entrance to the womb so you will only have a biopsy of this area if it is necessary. It is usually done in women who have abnormal cells on the cervix that are starting to turn into an invasive cancer. If you are further along in your pregnancy, your specialist may talk to you about having the biopsy after the baby is born.

Because there is more risk of bleeding in pregnancy, you may have it done in an operating theatre rather than as an outpatient. The doctor uses a small metal loop with an electric current to remove a small piece of the cervix. Your specialist may recommend you have it done under a general anaesthetic.

We have more information about CIN (cervical intra-epithelial neoplasia) that explains how abnormal cells are treated.

You can read more general information about tests in our information on the type of cancer you have.

Waiting for test results

Waiting for test results is a difficult time. It may take from a few days to a couple of weeks for the results of your tests to be ready. Try to talk with your partner, if you have one, family or a close friend about how you are feeling. Your specialist nurse can also provide support.

You can also talk things over with our cancer information nurse specialists on 0808 808 00 00.

When I fell pregnant, we were thrilled. But at 12 weeks I found a lump in my breast and my doctor sent me for tests. The results were devastating. I had cancer.

Polly