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Some cancer treatments can make it harder or impossible to have children later. Before treatment, your team should discuss this and, if you want, refer you quickly to a fertility specialist. Freezing sperm, eggs, embryos or ovarian tissue are the established options; an injection to rest the ovaries during chemotherapy can be added for some women with breast cancer but does not replace freezing.
Every person whose treatment may affect fertility should be told about the risk and the options before treatment, at the earliest opportunity where treatment is urgent (NICE NG257, 2026; ASCO 2025), and those who are interested or unsure referred promptly to a reproductive specialist (ASCO). NICE offers sperm cryopreservation, and oocyte or embryo cryopreservation, to people of reproductive age facing treatment likely to make them infertile, and ovarian tissue cryopreservation when oocyte or embryo storage is not feasible, for example before puberty; NHS-funded preservation is not bound by the usual eligibility criteria such as the lower age limit, and storage is reviewed at least every 5 years.
ESHRE (2020) recommends the GnRH antagonist protocol for ovarian stimulation for its speed and safety (strong), random-start stimulation as an option in urgent cycles (weak), and concurrent letrozole in oestrogen-sensitive cancers (good practice point). GnRH agonists during chemotherapy should be offered as an option for ovarian function protection in premenopausal women with breast cancer (ESHRE, strong), but not instead of cryopreservation (ESHRE; ASCO 2025: an adjunct only, in breast cancer). ASCO adds that testicular tissue freezing in prepubertal boys is experimental, that ovarian tissue cryopreservation is the only established method before puberty in girls, and that sperm collected soon after starting treatment may carry more genetic damage.
Why: The window closes once treatment starts; a short conversation now keeps choices open.
“Discuss fertility preservation as an option with people who are preparing for medical treatment, or who have a medical condition, that is likely to impair their fertility. For people who need urgent treatment, this discussion should take place at the earliest possible opportunity.”
Why: Specialists can explain the options and start them quickly, often without delaying cancer treatment.
“Patients interested in or uncertain about FP should be referred to reproductive specialists.”
Why: Sperm banking is quick, established and is best done before the first dose.
“Offer sperm cryopreservation to men (and boys), and trans women and non-binary people with male reproductive organs who are of reproductive age, and who are preparing for medical treatment, or who have a medical condition, that is likely to make them infertile.”
Why: Chemotherapy can damage sperm made in the weeks after it starts.
“Males should be advised of potentially higher genetic damage risks in sperm collected soon after cancer-directed therapy initiation and completion.”
Why: Frozen eggs or embryos are the established ways to keep the chance of a pregnancy later.
“Offer oocyte or embryo cryopreservation (as appropriate) to women (and girls), and trans men and non-binary people with female reproductive organs who are of reproductive age, and who are preparing for medical treatment, or who have a medical condition, that is likely to make them infertile.”
Why: ESHRE prefers this protocol because it is feasible when treatment is urgent, takes a short time and is safe.
“For ovarian stimulation in women seeking FP for medical reasons, the GnRH antagonist protocol is recommended for its feasibility in urgent situations, short time and safety reasons”
European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 · STRONG, very low quality evidence
Why: Letrozole keeps oestrogen levels lower while the ovaries are stimulated.
“In ovarian stimulation for FP in oestrogen-sensitive diseases the concomitant use of anti-oestrogen therapy, such as letrozole, is probably recommended.”
European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 · GPP (good practice point)
Why: Ovarian tissue can be removed and frozen without hormone stimulation, and later put back to try to restore fertility.
“Consider ovarian tissue cryopreservation when oocyte or embryo cryopreservation is not feasible, for example, in girls before puberty.”
Why: Resting the ovaries during chemotherapy helps protect how they work, but the evidence that it keeps the chance of pregnancy is limited.
“GnRH agonists during chemotherapy should be offered as an option for ovarian function protection in premenopausal breast cancer patients receiving chemotherapy; however, limited evidence exists on their protective effect on the ovarian reserve and the potential for future pregnancies”
European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 · STRONG, high quality evidence
Why: These decisions come at the same time as a cancer diagnosis and are hard to make quickly.
“It is recommended to provide decision aids to patients who are considering FP”
European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 · STRONG, low quality evidence
Why: Storage depends on renewed consent and on whether the person still needs it.
“Organise follow-ups at least every 5 years with people who have had their material preserved to determine whether or not there is a need to continue NHS-funded storage.”
How care is usually carried out, read from the guidelines and standards cited. Your own team's protocol and their judgement come first; this page is for understanding it, not for doing it yourself.
NICE NG257 (2026) and ASCO (2025) are the most recent and agree: discuss fertility before treatment, refer quickly, offer sperm, oocyte or embryo cryopreservation, and use ovarian tissue cryopreservation where egg or embryo storage is not feasible, including before puberty. ESHRE (2020) gives the most detail on how, with graded recommendations for the stimulation protocol and for each method. On GnRH agonists the three agree that they do not replace cryopreservation; ESHRE recommends offering them for ovarian protection in premenopausal women with breast cancer (strong, high quality evidence) and ASCO allows them as an adjunct in breast cancer, while ESHRE says the evidence for their effect on ovarian reserve and future pregnancy is limited. ASCO also allows GnRH agonists to stop periods in people who need urgent treatment for an oncological emergency, a different purpose. ESMO's 2020 guideline could not be read.
NICE 2026 · ASCO, Journal of Clinical Oncology 2025 · European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 · ESMO, Annals of Oncology 2020
Where it differs: Says GnRH agonists should not replace established methods and may be offered as an adjunct to females with breast cancer, and may be offered for menstrual suppression when urgent treatment is needed.
Evidence: ASCO 2025, read as an abstract; grades not seen. ESHRE grades its breast cancer recommendation strong on high-quality evidence.
ASCO, Journal of Clinical Oncology 2025 · European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020
Where it differs: Offers preservation after treatment to people who did not have it before, or did not store enough eggs or embryos.
Evidence: ASCO 2025, read as an abstract.
Where it differs: Collects immature eggs without full stimulation and matures them in the laboratory, where stimulation is not feasible.
Evidence: ASCO 2025 calls it an emerging method that may be offered; ESHRE (2020) says it requires specific expertise and that maturation after removal of ovarian tissue is experimental.
ASCO, Journal of Clinical Oncology 2025 · European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020
Fewer than half of patients starting treatment that can damage fertility have a documented fertility discussion or referral, with worse rates for women, minorities and patients outside academic centres. An order-set trigger that refers every patient under 40 to reproductive medicine unless they actively decline would make the conversation routine and timely.
| Recommendation | Grade, as printed | Source |
|---|---|---|
| GnRH antagonist protocol for ovarian stimulation for fertility preservation | STRONG, very low (⊕◯◯◯) | European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 |
| Random-start ovarian stimulation in urgent cycles “In urgent FP cycles, random-start ovarian stimulation is an option” | WEAK, low (⊕⊕◯◯) | European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 |
| Oocyte cryopreservation as an established option “Oocyte cryopreservation should be offered as an established option for FP” | STRONG, low (⊕⊕◯◯) | European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 |
| Embryo cryopreservation as an established option “Embryo cryopreservation is an established option for FP” | STRONG, low (⊕⊕◯◯) | European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 |
| Ovarian tissue cryopreservation where oocyte or embryo storage is not feasible, or by preference, before moderate or high-risk treatment “It is recommended to offer OTC in patients undergoing moderate/high-risk gonadotoxic treatment where oocyte/embryo cryopreservation is not feasible, or at patient preference” | STRONG, low (⊕⊕◯◯) | European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 |
| GnRH agonists during chemotherapy for ovarian protection in premenopausal breast cancer | STRONG, high (⊕⊕⊕⊕) | European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 |
| GnRH agonists not instead of cryopreservation in breast cancer “In women with breast cancer, GnRH agonists during chemotherapy should not be considered an option for FP instead of cryopreservation techniques” | STRONG, moderate (⊕⊕⊕◯) | European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 |
| GnRH agonists in cancers other than breast cancer “In malignancies other than breast cancer, GnRH agonists should not be routinely offered as an option for ovarian function protection and FP without discussion of the uncertainty about its benefit” | STRONG, very low (⊕◯◯◯) | European Society of Human Reproduction and Embryology (ESHRE), Human Reproduction Open 2020 |
Shares Default fertility preservation referral for every patient under 40 before treatment, Fertility in boys and young men treated for cancer, including testicular tissue banking, Fertility in girls and young women treated for cancer, including ovarian tissue freezing, Goserelin / leuprolide (ovarian function suppression) and the tags protocol, fertility.
Shares Goserelin / leuprolide (ovarian function suppression), National Institute for Health and Care Excellence, Letrozole (and other aromatase inhibitors), American Society of Clinical Oncology (ASCO) and the tags protocol, survivorship.
Shares Default fertility preservation referral for every patient under 40 before treatment, Fertility in girls and young women treated for cancer, including ovarian tissue freezing, Goserelin / leuprolide (ovarian function suppression), Leuprolide (leuprorelin) and GnRH agonists and the tag survivorship.
Shares National Institute for Health and Care Excellence, American Society of Clinical Oncology (ASCO) and the tags protocol, survivorship.
Shares National Institute for Health and Care Excellence, American Society of Clinical Oncology (ASCO) and the tags protocol, survivorship.
Shares American Society of Clinical Oncology (ASCO) and the tags protocol, survivorship.
Shares Goserelin / leuprolide (ovarian function suppression), Leuprolide (leuprorelin) and GnRH agonists, National Institute for Health and Care Excellence, Letrozole (and other aromatase inhibitors) and the tag protocol.
Shares American Society of Clinical Oncology (ASCO) and the tags protocol, survivorship.