Making cancer treatment decisions during pregnancy

There are different things your doctors will think about when deciding on the best treatment options for you.

For example:

• how many weeks pregnant you are
• the type of cancer and its stage (how far it has grown or if it has spread)
• how slowly or quickly the cancer is growing
• if the aim of treatment is to cure the cancer or to control it.

You should be involved in decisions about your treatment and pregnancy. Your doctors and nurses will talk to you about your feelings and preferences.

How far along you are in your pregnancy affects the timing of different treatments, particularly chemotherapy.

A pregnancy usually lasts for about 40 weeks. It is divided into periods of around 3 months, called trimesters. During each trimester, the baby goes through different stages of development.

First trimester – week 0 to 13 (month 0 to 3)

The baby is developing and its organs and limbs are forming. Doctors usually avoid giving chemotherapy during this time. Some types of surgery may need to be delayed.

Second trimester – week 14 to 27 (month 4 to 6)

The baby is growing quickly and the lungs and other organs are developing. You can have chemotherapy any time from 14 weeks onwards. You can also have some types of surgery. At 24 weeks, the baby has a chance of surviving if it is born.

Third trimester – week 28 onwards (month 7 to 9)

This is the final stage of growth when the baby moves into position for birth. If you are diagnosed with cancer during this time it may be possible to:

• delay treatment until after the baby is born, depending on the type of cancer
• have treatment to control the cancer until the baby is born
• have the baby delivered early, if neonatal doctors think the baby can cope, so you can start treatment.

Doctors try to give you the same treatment as they would give to a woman with the same type of cancer who is not pregnant. Depending on the treatment you need, doctors may recommend delaying or changing treatment to help protect the baby. Your doctor will talk to you before you make any decisions about your pregnancy and treatment.

Doctors also look at the stage of the cancer. If the cancer is bigger, doctors may advise starting treatment as soon as possible. They also look to see if the cancer is a type that grows slowly, or if it is likely to grow quickly.

Slow-growing cancers

Doctors may be able to watch (monitor) a cancer that is growing slowly during pregnancy. If the cancer starts to grow, they usually recommend you start treatment. If you are diagnosed at a later stage in pregnancy they may advise delaying treatment until after the baby is born.

Fast-growing cancers

With fast growing cancers doctors usually recommend you start treatment straightaway. If your pregnancy is at an early stage, they usually talk to you about deciding to end the pregnancy. This is because the cancer is a serious risk to your health. It means they can then give you the best possible treatment for your situation. You will be given lots of support to help you cope with this distressing situation.

If the cancer is fast growing and your are diagnosed in your third trimester, doctors may advise that the baby is delivered early. This is usually if you have a certain type of leukaemia or lymphoma. You start intensive chemotherapy straight after the baby is born.