This page looks at why it is important to avoid pregnancy during and shortly after treatment for breast cancer. Also included are some of the choices you might have as birth control during this time.
Avoiding pregnancy during treatment
It’s important not to get pregnant if you're having:
- hormone therapy
- targeted cancer drugs
These treatments could harm your developing baby.
It’s important to use reliable contraception as soon as you start treatment. Some treatments can make you infertile but this doesn't happen immediately, so you should use contraception throughout your treatment.
Talk to your healthcare team as soon as possible if you have breast cancer and you find out you're pregnant. They can discuss what this means for the pregnancy and how this might affect your treatment. In some situations, your cancer treatment can be rearranged or delayed so that you can have your baby.
Birth control choices
Talk about your contraception choices with your GP, or your cancer specialist doctor or nurse. Most doctors do not advise women to use the contraceptive pill because of the possibility that the hormones might affect any remaining breast cancer cells.
The withdrawal method and rhythm methods are not safe enough to prevent pregnancy. There are a number of alternatives, talk them through with your partner or someone you trust.
Your GP or specialists at the contraception clinic can give you more detailed information about your options. You could try:
- barrier methods – condoms or the cap
- barrier methods used with lubricating jelly if you need extra moisture during sex
- a coil (IUD) – this is a small T shaped device that a doctor or nurse puts into your womb. It doesn’t release hormones and can stay in for 5 to 10 years
- sterilisation – some women use this to stop the risk of getting pregnant if they are sure they don’t want children in the future
The Mirena coil
The Mirena coil releases a small amount of progesterone but we are not sure how much of this goes into other parts of the body. Because of this, the manufacturers don't recommend using the Mirena coil if you have had breast cancer.
The combined oestrogen and progesterone pill might be used if you can’t use any other methods of contraception.
The morning after pill
Most breast cancer specialists say that you can use the morning after pill. This is because a single dose of hormones is unlikely to affect your breast cancer and it is the best thing to do in a difficult situation.
Pregnancy after breast cancer
Most doctors advise women that it is best to wait for 2 years after treatment before getting pregnant.
This is because breast cancer is most likely to come back within the first 2 years after you are diagnosed. Having treatment for breast cancer that has come back could be very difficult if you are pregnant or you have a young baby.
Ask your doctor whether there are any risks if you become pregnant. Most studies have found that pregnancy after treatment for breast cancer does not increase the risk of cancer coming back.
Effect of treatment on fertility
Some women are able to have children naturally after treatment for breast cancer. Other women are unable to become pregnant after treatment.
Not being able to have children or being unsure if you are able to get pregnant can be very difficult to cope with. This can be the case even if you already have children. It can take some time to come to terms with.
Allow yourself some time to adjust and express your sadness. When you feel ready it might help to talk to your partner, family member or close friend.
There are now a number of ways of preserving fertility. Research is ongoing to find out how well they work and how safe they are for women with breast cancer.