Fertility and contraception before and during cancer treatment

How can treatment affect fertility?

Chemotherapy can damage eggs or the cells that make sperm. Surgery may remove or affect reproductive organs. Radiotherapy to the pelvis, testicles or certain parts of the brain can affect reproduction, and some hormone treatments delay the time when pregnancy can be considered. The risk depends on the treatment, dose, age and fertility before cancer.

Effects may be temporary or permanent. A period stopping during treatment does not prove permanent infertility, and a period returning does not tell you the full picture about egg supply. Similarly, normal sexual function does not prove that sperm production is normal.

Ask about your actual treatment rather than relying on the experience of someone with a different cancer. This discussion is also relevant before treatments such as stem-cell transplantation, which can carry a substantial risk to fertility.

What should happen before treatment?

Your oncology and fertility teams should agree whether any preservation procedure can be completed safely within the time available. Some cancers need urgent treatment, so a delay may not be appropriate. Do not postpone treatment yourself while searching for a clinic.

At the fertility consultation, discuss the likely benefit, possible risks, time needed and what future use of stored sperm, eggs or tissue would involve. Ask about the cost of collection, storage and later treatment, without assuming these are included in one fee. Access and arrangements vary between centres.

If treatment has already started, still ask for a fertility referral. There may be useful advice or options after treatment. Tell the specialist exactly which medicines you have received and when. Freezing sperm or collecting eggs during or soon after some treatments may be unsuitable because treatment can damage these cells.

Options for people who produce sperm

Freezing sperm before treatment is an established option. A semen sample is collected and stored for possible future fertility treatment. If giving a sample is difficult or no sperm is found, a specialist may discuss other methods of collection, including obtaining sperm directly from the testicle in selected circumstances.

The number of samples and the urgency depend on the situation. Ask early even if treatment is due to start soon; the teams can determine what is feasible. Do not assume that an earlier low sperm count means there is nothing worth discussing.

For boys who have not reached puberty, freezing testicular tissue is still experimental and should only be offered within an appropriate clinical trial. It is not an established way to preserve fertility.

Options for people who have ovaries

Freezing eggs or embryos is an established approach. Medicines stimulate the ovaries, eggs are collected and then frozen unfertilised or fertilised with sperm to create embryos. The choice involves personal preferences, medical circumstances and consent. Freezing eggs does not require choosing a sperm provider at that time.

The process needs coordination and monitoring. In many circumstances, stimulation can start without waiting for the next menstrual period, but the oncology and fertility teams must decide what is safe. Hormone-sensitive cancers require a tailored approach.

Freezing ovarian tissue is another established option for selected patients, including some who cannot undergo egg collection. It involves surgery to remove and store tissue. Suitability depends on age, treatment and the cancer itself.

With some cancers, especially blood cancers, the possibility of cancer cells being present in the tissue needs careful specialist consideration before it could be put back.

Other options may include moving the ovaries away from a planned radiation field or fertility-sparing surgery for selected cancers. These measures are cancer-specific. Preserving an ovary does not always preserve the ability to carry a pregnancy if treatment also affects the womb.

What about injections to protect the ovaries?

Some injections temporarily switch off the ovaries. They may be offered alongside chemotherapy for breast cancer to reduce the risk of losing ovarian function. They do not guarantee future fertility and should not replace egg, embryo or ovarian-tissue freezing when those options are suitable.

Ask which aim applies in your case: reducing the risk of loss of ovarian function, controlling menstrual bleeding or another treatment reason. These are related but different goals. Do not assume that an injection which stops periods is reliable contraception.

Why does contraception still matter?

Some cancer medicines can harm a developing baby, and the body may still release an egg or produce sperm despite treatment. Use the contraception plan agreed with your team if you or a partner could become pregnant. The advice applies to both people who might carry a pregnancy and people whose sperm could start one.

There is no single safe waiting period after all cancer treatments. The interval depends on the medicine, the person taking it and the wider cancer plan. Ask for the exact duration in writing and have it checked when treatment changes. Do not replace drug-specific advice with a general rule from the internet.

Choosing a method that suits your cancer treatment

Your team should consider your cancer, blood-clot risk, bleeding or infection concerns, other medicines and preferences. Non-hormonal contraception is usually the first choice after breast cancer; hormonal methods are generally unsuitable during active breast cancer treatment. Ask which method offers reliable protection in your situation.

Vomiting, diarrhoea and some drug interactions can affect oral contraception. A condom may be advised to protect a partner from exposure to drug residues in body fluids, while additional contraception may be needed for reliable pregnancy prevention. Ask about both purposes rather than assuming one instruction covers everything.

If unprotected sex occurs, contraception fails or pregnancy is possible, contact the team promptly. Emergency contraception and pregnancy assessment are time-sensitive, and the choice may be affected by medicines. Do not wait until the next routine appointment or make treatment changes without urgent advice.

Thinking about pregnancy after treatment

Arrange a joint review before trying for a pregnancy. The discussion may include cancer status, the time since treatment, ongoing medicines and whether heart, lung or other health checks are needed. Fertility tests may help, but they cannot promise a pregnancy or a healthy baby.

Sperm tests can assess sperm production. Blood tests and ultrasound can help assess the ovaries, but a result about egg supply is not the same as a prediction of natural pregnancy. If stored material is available, the fertility team can explain when and how it could be used.

If you carry an inherited gene change that increases cancer risk, ask whether genetic counselling would help with family planning. A counsellor can explain what it may mean for a child and the choices available to you. These are personal decisions.

Support for difficult decisions

Fertility discussions can bring grief, uncertainty or pressure, particularly when treatment decisions are urgent. Ask for counselling if helpful. A partner or family member can join with your permission, but you should also have space to discuss your own wishes privately. For children and teenagers, age-appropriate involvement and parent or guardian consent are important.

Common questions

Related reading

• Life after cancer treatment↗
• Sexual health and intimacy during and after cancer treatment↗
• Early menopause and cancer treatment↗