Fertility preservation and treatment in pregnancy

01Purpose and principlesWhat the treatment does and how it fits into care.

Cancer and its treatment can impair fertility through depletion of ovarian follicles, damage to spermatogonial stem cells, endocrine-organ injury, pelvic or cranial irradiation and surgery that removes or disrupts reproductive anatomy. Risk is individual: treatment class and cumulative exposure interact with age, baseline reserve, tumour site and prior therapy. The practical objective is not to promise future fertility, but to preserve reasonable options without compromising cancer control. Every patient of reproductive potential should be offered an early, documented conversation, including those who are young, single, LGBTQ+, already have children or have an uncertain prognosis.

Fertility preservation is an urgent parallel pathway. A fertility specialist estimates what is technically possible within the oncological window. Sperm collection can often occur promptly and multiple samples may be stored when time permits. Controlled ovarian stimulation with oocyte or embryo cryopreservation commonly takes around two weeks and can often begin independently of cycle phase. Ovarian tissue collection avoids stimulation but is more invasive and is not suitable for every malignancy because reimplantation might reintroduce tumour cells. Testicular tissue preservation remains specialist and often experimental. Gonadotrophin-releasing hormone agonists may protect ovarian function during selected chemotherapy, but do not replace discussion of cryopreservation.

Cancer in pregnancy requires two patients but maternal treatment benefit remains central. Establish gestational age, tumour histology and stage accurately, then discuss continuation of pregnancy, timing of therapy and delivery without coercion. Ultrasound and MRI without gadolinium are useful, while CT, radiography and nuclear imaging can be justified when the result changes urgent care; fetal dose is minimised with radiology and medical-physics advice. Surgery is possible in any trimester when necessary. Cytotoxic chemotherapy is generally avoided during first-trimester organogenesis, but selected disease-specific regimens can be delivered in later pregnancy. Endocrine treatment, many targeted agents and immune-checkpoint inhibitors are usually deferred because fetal safety is inadequate or recognised harm exists.

Birth planning is part of treatment, not an afterthought. Avoid chemotherapy close to delivery so maternal and neonatal marrow can recover, use the obstetrically safest mode rather than routine caesarean section, and aim for fetal maturity when maternal disease allows. Placental histology may be needed in tumours with recognised placental spread. Breastfeeding depends on the specific medicine and washout interval and is usually incompatible with ongoing cytotoxic or many targeted treatments. After treatment, revisit ovarian or testicular endocrine function, contraception, stored tissue, genetic risk, timing of pregnancy and the patient's evolving goals rather than treating the pre-treatment consent as a complete survivorship plan.

Key points

Ask about future fertility and pregnancy possibility at diagnosis, before surgery, systemic treatment or radiotherapy closes an option; record the patient's values without assuming them from age, parity, sex or relationship status.
First-line fertility triage assesses treatment urgency, ovarian or testicular reserve, expected gonadotoxicity and safe time available; urgent referral runs in parallel with cancer staging rather than after it.
Embryo or oocyte cryopreservation is the established option for many post-pubertal patients with ovaries when a short delay is oncologically safe; sperm cryopreservation is preferred before gonadotoxic treatment for patients producing sperm.
Ovarian-tissue cryopreservation can be considered when treatment cannot wait for stimulation or for selected prepubertal patients, but requires a specialist service and disease-specific assessment of malignant-cell reseeding risk.
Gonadotrophin-releasing hormone agonist ovarian suppression may reduce ovarian failure during some chemotherapy but is an adjunct, not a substitute for proven cryopreservation when that is feasible.
Cancer imaging and treatment during pregnancy are selected by gestation, tumour biology and maternal benefit; necessary maternal diagnosis should not be abandoned because of fetal radiation anxiety.
Avoid methotrexate, tamoxifen and other known teratogens during pregnancy; most cytotoxic chemotherapy is avoided in the first trimester, while selected regimens can be used after organogenesis through a specialist protocol.
Plan the final treatment dose and delivery interval to allow marrow recovery, avoid elective iatrogenic prematurity where possible, and agree neonatal assessment, breastfeeding compatibility and postpartum treatment restart before birth.

02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.

High gonadotoxicity

Alkylating exposure, stem-cell transplantation, pelvic or testicular radiotherapy and gonadal surgery carry substantial, dose- and age-dependent risk of permanent reproductive failure.

Time-critical referral

A curative regimen due within days requires same-day fertility contact so feasible preservation is chosen without an unsafe cancer-treatment delay.

Pregnancy at diagnosis

Amenorrhoea, nausea or a positive test during staging changes imaging, prescribing and consent but does not remove the need for definitive diagnosis.

Treatment-related ovarian failure

Amenorrhoea, vasomotor symptoms and low oestrogen may indicate ovarian insufficiency, but menstruation alone does not establish preserved fertility.

Male reproductive injury

Reduced semen quality can predate therapy from systemic illness and may worsen after chemotherapy, testicular radiation or retroperitoneal surgery.

Acute pregnancy complicationRed flag

Bleeding, contractions, reduced fetal movement, hypertension or sepsis needs immediate maternity assessment while cancer complications are evaluated in parallel.

Red flags requiring action

A new cancer diagnosis in pregnancy must not be deferred automatically until after delivery; delay may reduce the chance of cure.
Fever after systemic anticancer treatment is suspected neutropenic sepsis irrespective of pregnancy and needs immediate empirical antibiotics.
Breathlessness, pleuritic pain, unilateral leg swelling or collapse raises pregnancy- and cancer-associated venous thromboembolism risk and requires urgent assessment.
Pelvic pain, vaginal bleeding, fluid loss, reduced fetal movement or contractions needs same-day maternity triage alongside oncology review.
Any planned gonadotoxic treatment, pelvic radiotherapy or reproductive-organ surgery creates a time-limited fertility discussion before treatment starts.

03Assessment before treatmentTests and checks that guide safe selection.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
First-line reproductive and treatment assessmentFirst stepFirst line
Why
Define pregnancy status, treatment urgency, expected gonadotoxicity and the patient's reproductive goals before therapy.
Interpretation and limitations
Document last menstrual period or pregnancy testing where relevant, pubertal status, parity, prior fertility, planned agents, radiation field, cumulative doses and safe delay; no single ovarian-reserve value can guarantee future fertility.
02
Semen analysis and cryostorage assessment
Why
Establish whether ejaculated sperm can be banked before gonadotoxic treatment.
Interpretation and limitations
Cryopreserve usable samples even when count or motility is reduced; surgical sperm retrieval may be considered urgently when ejaculation is impossible or no sperm is present.
03
Anti-Müllerian hormone and antral follicle count
Why
Help a fertility service estimate ovarian response and plan stimulation.
Interpretation and limitations
These are reserve and response markers, not direct tests of natural conception or a reason to deny preservation; values are interpreted with age and time available.
04
Pregnancy dating and fetal assessment
Why
Establish gestational age, viability, anatomy and a baseline for treatment planning.
Interpretation and limitations
Specialist ultrasound is first-line for fetal assessment; surveillance frequency follows gestation, maternal therapy and obstetric risk rather than a universal schedule.
05
Cancer staging with pregnancy optimisation
Why
Obtain the anatomical and histological information required for curative or life-prolonging treatment.
Interpretation and limitations
Use ultrasound or MRI where diagnostically adequate, but perform justified CT or radiography when delay or inferior staging would harm the mother; involve radiology and physics to estimate and minimise fetal dose.
06
Placental pathology when indicated
Why
Look for placental metastasis in tumour types or stages with recognised transplacental risk.
Interpretation and limitations
A specialist plan is particularly relevant for melanoma and disseminated maternal disease; a positive placenta changes neonatal examination and follow-up.

04Treatment approachPreparation, options, escalation and aftercare.

01Before treatmentPreserve options without losing cancer controlFirst stepA reproductive-age or prepubertal patient is offered potentially gonadotoxic treatment.

1Explain the estimated treatment-specific risk, ask what future biological parenthood means to the patient and obtain consent for urgent fertility referral and storage decisions.
2Send a complete referral with diagnosis, stage, proposed regimen, start deadline, infection and blood-count constraints, and whether ovarian stimulation or a procedure is oncologically safe.
3Choose sperm, oocyte, embryo or tissue preservation with the specialist team, document limitations and legal storage consent, and confirm that treatment start remains owned by oncology.

02Pregnancy diagnosisStage accurately and agree intentCancer is suspected or confirmed during pregnancy.

1Confirm histology and clinically necessary stage using pregnancy-optimised imaging; do not accept an under-staged cancer when safer justified imaging can answer the question.
2Hold an early meeting involving tumour-site oncology, fetal medicine, obstetrics, surgery, anaesthesia, neonatology and pharmacy, with genetics or psychological support when relevant.
3Explain maternal outcomes, fetal uncertainties, alternatives and the option of pregnancy termination where legally and clinically relevant, supporting the patient's informed decision without directing it.

03TreatMatch therapy to gestation and tumourActive cancer treatment is required before delivery.

1Perform necessary surgery with pregnancy-adapted anaesthesia and thrombosis planning; do not postpone urgent curative surgery solely because of trimester.
2Avoid cytotoxic chemotherapy during first-trimester organogenesis when possible; after the first trimester use only disease-specific regimens with established pregnancy experience and maternal dose intensity.
3Defer contraindicated endocrine, targeted, immune and radiotherapy exposure unless a senior multidisciplinary risk-benefit decision identifies no safer effective route, and record fetal monitoring and maternal toxicity plans.

04Delivery and aftercareCreate a safe treatment-delivery intervalA pregnant patient approaches the final antenatal treatment cycle or delivery.

1Coordinate the last systemic dose and planned birth so marrow recovery is expected, while allowing urgent delivery for maternal or fetal indications and avoiding unnecessary prematurity.
2Agree mode and place of birth, blood-product and infection contingencies, placental examination where indicated, neonatal blood tests and whether breastfeeding is compatible with every current medicine.
3Restart postpartum cancer treatment at the clinically appropriate time, provide effective contraception, and revisit stored gametes, gonadal function, future pregnancy timing and psychosocial support during survivorship.

05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.

May reduce chemotherapy-associated premature ovarian insufficiency in selected premenopausal patients while definitive cryopreservation options are considered.

Goserelin ovarian suppression

When selected as an adjunct, give goserelin 3.6 mg by subcutaneous implant every 28 days, starting before or as close as feasible to chemotherapy and continuing through the gonadotoxic course under the oncology protocol.

It does not guarantee fertility and must not replace oocyte or embryo discussion. Exclude pregnancy, explain vasomotor and bone effects and coordinate timing in hormone-sensitive cancer with the treating oncologist.

Allows curative or life-prolonging systemic treatment for selected cancers when deferral would compromise maternal outcome.

Cytotoxic chemotherapy after organogenesis

Use the full maternal, body-surface-area-based disease regimen selected by the specialist MDT after the first trimester; do not empirically reduce dose because of pregnancy and stop sufficiently before planned delivery for marrow recovery.

Avoid during first-trimester organogenesis where possible. Review placental transfer, fetal growth, maternal pharmacokinetics, neutropenia and delivery timing agent by agent; this is not a single interchangeable regimen.

Provides important adjuvant endocrine therapy outside pregnancy for susceptible breast cancer, usually restarted postpartum when safe.

Tamoxifen

Do not administer tamoxifen during pregnancy; use effective non-hormonal contraception during treatment and for the product-specific washout interval before conception.

Fetal harm is possible and breastfeeding is generally incompatible. A temporary interruption for pregnancy requires oncology agreement because recurrence risk, duration already completed and age materially change the decision.

06Complications, monitoring and follow-upAdverse effects, response and longer-term review.

Before gonadotoxic therapy, record preservation offer, response, chosen method, storage consent, treatment start date and who will communicate results or complications.
During pregnancy, monitor maternal disease and treatment toxicity to the same clinical standard as outside pregnancy, adding gestation-specific fetal growth and wellbeing surveillance.
Before each systemic dose, confirm gestational age, blood count, organ function, infection, thrombosis and the planned interval to delivery.
Review fetal growth and placental function at the specialist interval, recognising that a reassuring scan does not exclude later treatment or prematurity effects.
After treatment, assess menstrual or androgen symptoms and refer for reproductive endocrinology or semen testing when results will guide fertility or hormone-replacement decisions.
Maintain a survivorship record of cumulative gonadotoxic exposures, radiotherapy field, stored material, contraception, pregnancy advice and relevant inherited cancer risk.

07Special situationsVariants, exceptions and circumstances that change the usual approach.

Referral is not delay

Rapid fertility review can often run alongside staging and central-line preparation, preserving choice without losing the oncology timetable.

Menses are not fertility

Cycles may resume despite diminished reserve, while amenorrhoea can be temporary; reproductive plans need specialist interpretation rather than one symptom.

Imaging risk is comparative

The fetal risk of a justified diagnostic scan must be weighed against the maternal and fetal harm of missed stage or delayed emergency care.

Pregnancy dosing treats the mother

Empirical dose reduction can reduce cancer efficacy; regimen and timing are adapted by specialists without making subtherapeutic exposure the default.

Birth is a treatment transition

Marrow recovery, neonatal support, placental assessment, breastfeeding and postpartum restart all need named ownership before labour begins.

08Common pitfallsFrequent interpretation and management errors.

01
Assuming a patient does not value fertility because they already have children, are single or have a poor prognosis.
02
Waiting until chemotherapy consent is complete before making a fertility referral, leaving no safe preservation window.
03
Presenting gonadotrophin-releasing hormone agonist suppression as equivalent to sperm, oocyte or embryo cryopreservation.
04
Avoiding necessary staging CT and consequently giving pregnancy-modified treatment to an inadequately staged cancer.
05
Reducing maternal chemotherapy doses without a pharmacological or protocol reason.
06
Scheduling routine early delivery for convenience rather than balancing cancer urgency with avoidable prematurity.
07
Recommending breastfeeding without checking every anticancer medicine and its required washout interval.