Intrauterine systems (IUS) after cancer
Intrauterine systems (IUS) are a type of contraception. Some women should not use an IUS after cancer treatment. There are different types or brands of IUS. These include Mirena, Benilexa, Levosert, Jaydess and Kyleena.
This information is for people who have cancer or have had cancer. For more general information about the IUS, go to the NHS website.
What is an intrauterine system (IUS)?
An IUS is used as a type of contraception to prevent pregnancy. Women who have heavy periods might also have it make bleeding lighter.
A brand called Mirena is also used in combination with 
as part of hormone replacement therapy (HRT). It helps to protect the lining of your womb.
You have the IUS put into your womb like the contraceptive coil. But unlike the contraceptive coil, it releases a small amount of hormone into your womb every day. This hormone is levonorgestrel which is a man-made version of the hormone progesterone. It helps to prevent pregnancy in 2 ways:
- by thickening the mucus at the neck of the womb making it difficult for sperm to enter the womb
- by stopping the womb lining from thickening making it difficult for fertilised eggs to settle in the womb
The lining of the womb doesn’t thicken so you may have much lighter periods. Or your periods may stop completely.
Who shouldn’t use an IUS?
The manufacturers say that women shouldn’t use an IUS if they have had:
- cervical cancer or womb cancer
- liver cancer
hormone dependent cancers, including breast cancer - blood cancers, including leukaemia
- gestational trophoblastic tumours, such as molar pregnancy
Cancer of the womb or cervix
If you have cancer of the womb or cervix your doctor would usually advise against the use of an IUS. This is to avoid complications that an IUS might cause with the cancer or any treatment such as radiotherapy.
The main treatment for these cancers is surgery to remove the womb (hysterectomy). So in this situation, you wouldn’t physically be able to have the IUS in place.
The exception is some women with early stage womb cancer who still want to have children. They may have treatment with a progesterone tablet, or an IUS, or both. This is called fertility preserving treatment. The aim of the hormone treatment is to shrink the cancer and avoid or delay a hysterectomy. Anyone wanting to have fertility preserving treatment is usually seen at a specialist centre.
Liver cancer
The IUS may affect how your liver works. If you have had liver cancer or any type of liver disease, you should not use an IUS.
Hormone dependent cancers, including breast cancer
The IUS only releases a small amount of levonorgestrel. Doctors are not sure how much of it, if any, goes to other parts of the body. So it is not generally recommended if you have had a hormone dependent cancer, such as breast cancer.
There has been research looking at whether there is a link between the IUS and the risk of breast cancer. But this has mainly looked at risk in the general population. Few studies have focused on women who have had breast cancer.
If you are concerned you can talk to your GP, specialist or pharmacist. You can ask which contraception is best for you.
Blood cancers, including leukaemia
Due to your leukaemia and its treatment, you may not have enough platelets to help your blood clot normally. So your healthcare team may recommend you don’t have an IUS because of the risk of bleeding. There is a risk that this could cause heavier bleeding than normal.
You may be able to use it when there are no signs of your leukaemia (it is in remission). Talk to your healthcare team to check.
Gestational trophoblastic disease, such as molar pregnancy
Guidelines recommend that you should not use an IUS if you have recently been diagnosed with gestational trophoblastic disease (GTD). GTD includes molar pregnancy, invasive mole or choriocarcinoma.
You might be able to use an IUS after you have finished treatment. The timing of this depends on your type of GTD. Your specialist can talk to you about this.
