Cancer and pregnancy

pregnant pregnancy scan

About cancer during pregnancy

Cancer during pregnancy is very rare. Figures show cancer affects about 1 in 1,000 pregnancies. If you are diagnosed with cancer during your pregnancy, you will be cared for by a specialist team which will include a cancer doctor (oncologist), obstetrician, specialist nurses and midwives. This team is called the multidisciplinary team (MDT) and they will support you throughout your pregnancy and your illness.

They will discuss and devise a treatment plan with you, taking all the factors into consideration. They will address all your questions and concerns and take your preferences into consideration.

Remember to jot down your questions before your hospital appointments so you don’t forget anything.

If you do forget something or need to talk things over with someone, you can call a cancer nurse on our Support Line 1800 200 700 – they can help support you or put you in contact with someone who had been in a similar situation.

What types of cancers occur in pregnancy?

Any type of cancer can occur during pregnancy. However, the most common cancers diagnosed during pregnancy are breast cancer, melanoma, cervical cancer, lymphomas and leukaemia.

Being pregnant does not increase your risk of getting cancer.

Symptoms and diagnosis

Many of the symptoms of cancer are similar to those of pregnancy, including nausea and vomiting, abdominal pain, anaemia and fatigue. Breast changes – for example, a change in breast texture – can often happen as a normal occurrence during pregnancy. This, however, could be a symptom of breast cancer.

Because of the similarities in symptoms, sometimes diagnosis can be delayed. Talk to your GP and Obstetrician if you are worried about symptoms that develop during pregnancy.

Usually you will be able to have tests to diagnose or stage your cancer, but doctors sometimes will avoid using certain types of scans, such as bone, CT or PET scans. This is to protect the baby from any risk of exposure to the radiation used in these tests.

How is cancer treated during pregnancy?

Your multidisciplinary team (MDT) will discuss treatment options with you and decide on a treatment plan. Your treatment will depend on the stage of your pregnancy, the type of cancer you have, the stage the cancer is at and the aim of the treatment.

Cancer treatments used during pregnancy include surgery, chemotherapy and sometimes radiation therapy. If you are in your first 3 months of pregnancy (first trimester), your MDT may advise waiting until the second or third trimester before starting treatment. If the cancer is at a very early stage, they may advise waiting until the baby is born.


Breast cancer is one of the most common cancers during pregnancy and most people with breast cancer will have some type of surgery. Surgery is also the most common treatment for melanoma and cervical cancer.

Surgery is considered safe during pregnancy and will not harm your baby. The aim of surgery is to remove the cancer cells with the minimum risk of them returning.


Radiotherapy uses high-energy X-rays to destroy cancer cells. It is not usually used during pregnancy as it can harm the baby’s development or increase your risk of miscarriage. Doctors often wait until after the baby is born before giving radiotherapy. It can sometimes be given in an emergency if the area of the body to be treated is not near the womb and developing baby.


Chemotherapy uses anti-cancer drugs to kill cancer cells. Research shows that certain anti-cancer drugs are safe to use during pregnancy after 14 weeks, and will not harm the baby. You may need to stop treatment about a month before your due date as chemotherapy can increase your risk of infection and bleeding. Read more about chemotherapy treatment and side-effects.

Other drug therapies

Hormonal therapies, targeted therapies and immunotherapies are not often used to treat cancer during pregnancy as they can interfere with the development of the baby. Your MDT may decide to delay using these therapies until after the baby is born.

Monitoring during pregnancy

You may have more hospital/doctor appointments during your pregnancy to monitor your overall health, the progression of your illness – if treatment is delayed until after delivery – and the baby’s development.

If you are having chemotherapy during pregnancy, it can sometimes lead to a baby’s lower birth weight. It can also increase the risk of an early delivery. Regular check-ups and monitoring are important to pre-empt any potential issues and allow you and your MDT to plan accordingly. Talk to your obstetrician or midwife about any concerns you have about the baby’s development or delivering your baby.

After the baby is born

If your treatment finishes some weeks before your baby is born, you may be able to breastfeed straight away.

However, you may be in the middle of treatment or just starting treatment – and this can be a difficult time physically and emotionally. Your medical team are there for you but make sure you have support from family and friends to care for the baby while you are getting treatment.

Coping with a cancer diagnosis, treatment and a newborn baby at the same time is very difficult. Talk to one of our cancer nurses on the Support Line 1800 200 700 or call into your local Daffodil Centre. They can answer your questions, tell you about your local support services or send you publications that might be helpful.

Molar pregnancy

A molar pregnancy is when a growth of abnormal cells develops in the womb at the beginning of pregnancy. It is also known as gestational trophoblastic disease.

It is a rare condition, with about 1 pregnancy in 700 being molar. Nearly all molar pregnancies end in miscarriage.

Most molar pregnancies are benign (not cancerous). However, sometimes it can cause a rare form of cancer. Read more about molar pregnancies in our section on rare cancers.

pregancy scan

Medical content reviewed by:
Dr Donal O Brien, Consultant Gynae-Oncologist and Obstetrician, National Maternity Hospital
Sarah Belton, Gynae Oncology CNS, National Maternity Hospital

June 2022

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