Fertility and pregnancy in people diagnosed with CML

The outlook of Chronic Myeloid Leukaemia (CML) has improved dramatically over recent years.1 Most people with CML can now manage well on first-line tyrosine-kinse inhibitor (TKI) therapy and the disease makes little, if any, impact on their life expectancy.1 Understandably you might want to know what CML means in terms of your chances of having children. Unfortunately, there is still relatively little evidence about the effect of TKIs on fertility, pregnancy and the health of the baby, although the current recommendation is that women wishing to conceive should should stop treatment with TKIs prior to conception and ideally remain off TKI treatment throughout their pregnancy. However, the good news is that men and women with CML have had healthy babies.

Here we answer some FAQs:

Why is it important to use contraception?

Women who have the potential to become pregnant are advised to practise effective contraception and avoid becoming pregnant whilst on TKI therapy.1 Women who are taking TKIs have an increased risk of miscarriage and harm to the foetus and the current recommendation is that women who wish to conceive should stop treatment with TKIs before conception.1 If you are thinking of trying to conceive it is very important to speak to your doctor first so that you can agree a plan regarding your treatment.

Can I get pregnant and have a healthy pregnancy with CML?

Your doctor should discuss the potential impact of CML and its treatment on fertility with you at diagnosis.1 They may suggest that you consider fertility preservation through freezing your eggs or embryos.1 If you think you may want to have children in the future, and your doctor has not discussed it with you, make a note to ask about it at your next consultation.

Women with CML have had healthy pregnancies and healthy babies.1 However, pregnancy during CML needs to be closely managed by your healthcare team.1 It is very important to work with your doctor to discuss the risks and benefits and to agree a plan that is right for you. 

The current recommendation is that women who wish to conceive should stop treatment with TKIs before conception.1 If you’re thinking about trying to get pregnant, do not stop treatment without talking to your doctor first. The recommendations for treating your CML while you’re trying to conceive depend on your age, and your response to your current treatment.1

Treatment may not be necessary during pregnancy for some women who have achieved a deep and durable molecular response. For other women a medicine called interferon alpha (IFN-α) or leukapheresis (a technique used to remove abnormal white blood cells from the blood) might be recommended.1

Can I breastfeed?

The types of medication used to treat CML can be transferred into breastmilk and women on these medications are advised not to breastfeed.1 It is important to discuss breastfeeding, and alternatives, with your doctor. 

Can I become a father with CML?

If you are a man with CML who is thinking about starting a family, it is important that you talk to your doctor first. There is limited evidence available to help you make your decision.1

It is worth considering semen cryopreservation (sperm banking) if you think you may want to have children in the future because it is not possible to predict at diagnosis which treatments you may need later.1 If your doctor has not discussed this with you, you might want to make a note to yourself to ask about it at your next appointment. 

Will I pass CML to my child?

CML is not inherited because it is caused by a mutation in the body’s cells that happens after conception.2

  1. Palani R., Milojkovic D., Apperley J.F. (2016) Managing Pregnancy in Chronic Myeloid Leukemia. In: Hehlmann R. (eds) Chronic Myeloid Leukemia. Hematologic Malignancies. Springer, Cham.
  2. Lugo T., Pendergast A, Muller A. Chronic myeloid leukemia. 2016. Accessed May 2018.