Fertility, Pregnancy and Contraception — on Imatinib

The exact duration depends on how long you have been on imatinib, your molecular response, and your individual situation. Imatinib and its active metabolite clear pharmacologically within days, but ELN guidance recommends a supervised period off treatment — often several weeks — with close molecular monitoring throughout. Your oncologist will give you a specific plan. Do not stop imatinib and start trying without that conversation first.

Call your oncology team the same day. An accidental pregnancy on imatinib needs urgent review — not because all outcomes are necessarily bad, but because the decision about what to do next is complex and time-sensitive. Your oncologist will assess the risks based on how far along the pregnancy is and how well your disease is controlled. This conversation is confidential and your team will support you without judgement, whatever you decide.

There is no clear evidence from human studies that imatinib causes permanent infertility in women. In men, animal studies have shown effects on sperm, and there are limited human reports, but the picture is not definitive. The more important practical step is fertility preservation — egg freezing for women, sperm banking for men — before you start, when you still have the option. Ask your oncologist to refer you to a fertility specialist if you want to explore this.

This is a decision your oncologist makes based on your disease, your response to treatment, and the stage of pregnancy. Some patients with CML in very deep remission are managed through pregnancy with close monitoring and without a TKI for part of the pregnancy. Where treatment is needed, the choice of which medicine carries the least risk is made by the oncologist in consultation with a maternal-fetal medicine specialist. There is no single right answer — the decision is individual.

No. Imatinib is present in breast milk, and the EMA recommends that women on imatinib should not breastfeed. This applies for the duration of treatment and through the washout period after stopping. Formula feeding from birth is the safe approach if you are continuing imatinib. Discuss this with your oncologist and paediatrician before your baby arrives so there is a clear plan in place.

Imatinib may affect sperm quality, though the human evidence is limited. If you are a man of reproductive age starting imatinib and you want children in the future, sperm banking before your first dose is worth discussing with your oncologist. It is straightforward, it keeps your options open, and it is much easier to arrange before treatment than during it. If you are already on imatinib and now planning a family, ask your oncologist whether any precautions are needed before you try to conceive.