Chemotherapy and fertility: what to know before you start

Yes, chemotherapy can affect fertility, and the most important decisions about protecting it usually need to be made before the first cycle. Many chemotherapy medicines damage rapidly dividing cells, and the cells that produce sperm in men and the eggs and supporting cells in the ovaries in women are among those affected. Some treatments have little lasting effect on fertility; others, particularly certain medicine groups given at higher total amounts, and treatments combined with radiotherapy to the pelvis or high-dose treatment before a transplant, can reduce fertility significantly or end it. Age matters too. Younger people generally have more capacity to recover, while women nearer their natural menopause are more likely to lose fertility permanently.

Fertility preservation means storing sperm, eggs, embryos or reproductive tissue before treatment so there is a chance of having biological children later. The options work best, and some only work at all, before chemotherapy begins, because treatment can damage sperm and eggs quickly. Yet in busy clinics and under the stress of a cancer diagnosis, fertility is often not mentioned, or families feel it is not the right moment to ask. Months or years later, many survivors say that not being told about fertility was their greatest regret. If there is any chance that you, or your child, may want biological children in the future, ask your oncologist about fertility before treatment starts, even if it seems less important than the cancer right now. Your team can explain your risk, whether there is time for preservation, and refer you urgently to a fertility specialist.

Decide before cycle one where possible

Sperm banking can often be done within days; egg or embryo freezing usually needs a couple of weeks.

Not every cancer allows a delay

For some urgent or fast-growing cancers, treatment must start immediately. Your team will advise.

Fertility and contraception are both important

Even if fertility may be affected, pregnancy is still possible during treatment and must be avoided.

It cannot tell you how your own treatment will affect your fertility, or whether you will be able to have children later. The effects depend on many factors and cannot be predicted with certainty for any individual. Your oncologist and a fertility specialist can give a more personal estimate.

It also cannot promise that stored sperm, eggs or embryos will lead to a pregnancy. Preservation offers a chance, not a certainty, and success depends on age, the number and quality of what is stored, and later fertility treatment.

Cost is a real barrier

Egg and embryo freezing can be expensive and are rarely covered by insurance. Ask for estimates.

Unmarried patients

Unmarried women can freeze eggs rather than embryos. Discuss options and family views openly.

Religious and cultural views

Some families have views about assisted reproduction. Counselling can help you decide in line with your values.

Men often miss out

Sperm banking is simple, but men are frequently not offered it. Ask even if you are unsure.

Children and teenagers

Parents should ask about fertility before treatment starts, as some options exist for young people.

If treatment has already started

Options are more limited, but it is still worth asking about testing and future choices.

Emotional impact

Thinking about fertility during a cancer diagnosis is hard. Counselling and support help.

Other routes to parenthood

If fertility is lost, adoption and donor options may still make parenthood possible.

Why the window before treatment matters

Sperm and eggs are made by cells that divide actively, which is exactly what chemotherapy targets. Even a single cycle can damage sperm DNA and reduce the number of eggs in the ovaries. Once treatment has begun, sperm collected may carry damage, and stimulating the ovaries to collect eggs may no longer be safe or effective while blood counts are low. This is why fertility specialists and cancer organisations stress that the conversation about fertility should happen at diagnosis, before the first dose, whenever it is safe to allow the brief time needed. For men, this often means banking sperm within a day or two. For women, it may mean starting ovarian stimulation within days so that eggs or embryos can be frozen before treatment begins.

When treatment cannot wait

Sometimes the cancer is so aggressive, or a patient so unwell, that chemotherapy must start immediately. In these situations there may be no time for egg or embryo freezing, and sometimes not even for sperm banking. Your team should explain this clearly. Options such as ovarian suppression during chemotherapy, or ovarian or testicular tissue freezing, may still be considered in some centres. Fertility can also be tested after treatment, and other routes to parenthood remain possible. Not having time to preserve fertility is painful, but it is not the end of all options.

What to do next

Ask your oncologist how treatment may affect your fertility and whether there is time to preserve it, request an urgent fertility referral, discuss options and costs with your family, act before the first cycle where possible, and use reliable contraception during treatment.