Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Cycle control, hirsutism and fertility treatment in PCOS
Obstetrics and gynaecology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Stop teratogenic exposure before conception
Anti-androgens and some weight-management medicines can harm a pregnancy, while ovulation may return unexpectedly during PCOS treatment even before cycles become regular.
Action: Check pregnancy when relevant, confirm reliable contraception before anti-androgen use, and complete a documented preconception medicine review with appropriate washout before fertility treatment.
Purpose and principles
Match PCOS treatment to cycle, androgen, metabolic and fertility goals, prescribe safely, and escalate anovulatory infertility without exposing patients to avoidable pregnancy or medicine harm.
PCOS treatment works best when each intervention is tied to a stated goal. A person who wants contraception and fewer androgen symptoms may prefer a combined pill; someone wanting pregnancy needs ovulation treatment, not cycle suppression; someone with infrequent bleeding but no contraceptive need may choose periodic progestogen. Ask which symptom is most burdensome, what previous treatments achieved, whether pregnancy is desired now or later, and what risks or cultural considerations shape acceptability.
Offer sustainable lifestyle support to everyone, independent of body size, and treat symptoms at the same time. There is no single superior PCOS diet or exercise regimen. Support adequate nutrition, regular activity, reduced sedentary time, sleep and mental health. Weight management can be discussed when the person wants it, but avoid making weight loss a gatekeeper for contraception, hair treatment or fertility referral. Optimise hypertension, dysglycaemia, smoking and sleep apnoea before pregnancy.
Indications, selection and cautions
Cycle-control goal
A need for contraception, predictable bleeding or endometrial protection directs method selection before considering any effect on androgen symptoms.
Androgen-treatment goal
Hirsutism severity, hair-removal practices, acne, alopecia and distress determine whether cosmetic, combined hormonal or specialist anti-androgen therapy is appropriate.
Metabolic-treatment goal
Dysglycaemia, higher metabolic risk and preference may support metformin, while normal results and intolerance can favour non-pharmacological monitoring.
Anovulatory infertility
Irregular cycles and absent evidence of ovulation support induction only after pregnancy, semen, tubal context and other endocrine causes are assessed.
Treatment mismatch
Regular pill-withdrawal bleeds can meet cycle goals but do not demonstrate spontaneous ovulation, and anti-androgen improvement does not treat metabolic risk.
Red flags requiring action
New virilisation or rapidly progressive androgenic symptoms during treatment requires diagnostic reassessment rather than automatic dose escalation.
Chest pain, breathlessness, unilateral leg swelling, new focal neurological symptoms or severe headache while using combined hormonal contraception needs urgent thromboembolic assessment.
Assessment before treatment
01Pregnancy test and contraceptive reviewFirst step
Why
Prevent fetal exposure before hormonal, anti-androgen or ovulation-induction treatment.
Interpretation and limitations
A negative result is time specific; ensure ongoing contraception for teratogenic medicines and repeat testing before each monitored induction cycle as the protocol requires.
02Blood pressure and eligibility assessment
Why
Identify contraindications and interactions before combined hormonal contraception.
Interpretation and limitations
Hypertension, migraine aura, thromboembolic history, smoking and interacting medicines may shift the choice to a non-oestrogen method.
03Renal function and vitamin B12 risk
Why
Support safe metformin initiation and recognise a modifiable long-term adverse effect.
Interpretation and limitations
Reduced eGFR changes dosing or suitability; anaemia, neuropathy, restricted diet or prolonged exposure should lower the threshold for B12 measurement.
04Semen and tubal-context assessment
Why
Avoid treating presumed isolated anovulation while another important fertility factor remains unrecognised.
Interpretation and limitations
An abnormal semen analysis or tubal-risk history changes treatment efficiency and may move care toward a different assisted-conception pathway.
Treatment approach
01Cycle and contraceptionChoose endometrial protection by goalFirst stepSpontaneous bleeds are infrequent and pregnancy is not currently desired.+
1Exclude pregnancy, ask about abnormal bleeding and assess combined-hormonal eligibility, contraception preference and desire for androgen improvement.
2Offer an eligible combined pill, LNG-IUS, progestogen-only method or periodic oral progestogen with an explicit bleeding and review plan.
3Review tolerability, blood pressure where relevant, bleeding pattern and whether the chosen method still matches pregnancy intention.
02HirsutismLayer slow-acting treatments safelyTerminal facial or body hair causes distress after serious androgen excess has been excluded.+
1Offer safe cosmetic removal and, when eligible and wanted, combined hormonal contraception; explain that visible improvement commonly takes six months or longer.
Regimens, contraindications and interactions
Suppresses ovarian androgen production, raises SHBG, provides contraception and produces planned endometrial shedding for cycle control.
Combined oral contraceptive
Take one active oral tablet daily using the selected licensed 21-day, 24-day or tailored regimen, with any hormone-free interval defined by that product and contraceptive guidance.
Check UK contraceptive eligibility, blood pressure, migraine aura, smoking, venous and arterial thrombosis risk, liver disease and interacting medicines; counsel urgent thromboembolic symptoms.
Improves insulin action and metabolic outcomes and may assist cycle regulation in selected adults with PCOS.
Metformin
Start 500 mg orally once daily with food, increasing by 500 mg every one to two weeks toward a tolerated divided or modified-release dose, commonly 1.5–2 g daily.
Review eGFR, hepatic disease, acute hypoxia or dehydration and contrast procedures; gastrointestinal effects are common, and long-term use can lower vitamin B12.
Slows facial-hair growth and complements, rather than replaces, physical hair-removal methods.
Eflornithine 11.5% cream
Apply a thin layer to affected facial areas twice daily at least eight hours apart; assess by four months and stop if there is no benefit.
Use only on intact facial skin, wash hands after application and reduce frequency if irritation develops. Avoid during pregnancy, when planning pregnancy and while breastfeeding; hair growth returns after treatment stops.
Complications, monitoring and follow-up
Review cycle method, blood pressure and new contraindications after starting combined contraception, and reassess immediately after thromboembolic or neurological symptoms.
Assess metformin gastrointestinal tolerance during titration, renal function at clinically appropriate intervals and vitamin B12 when symptoms or risk factors arise.
Photographs or a consistent patient-reported scale can track hirsutism after at least six months; biochemical androgens are not a substitute for visible benefit and wellbeing.
For anti-androgens, repeatedly confirm effective contraception and follow agent-specific potassium, renal, liver and adverse-effect monitoring.
During ovulation induction, track follicular response, ovulation, pregnancy, multiple-pregnancy risk and cumulative cycles with pre-agreed escalation or stopping criteria.
Special situations
One medicine cannot meet every goal
A pill may control cycles and hair but prevents conception, while letrozole induces ovulation without providing long-term metabolic or endometrial care.
Hair response is delayed
Existing terminal hairs persist through their growth cycle, so effective androgen suppression should be judged after months and paired with removal methods.
Off-label can still be preferred
Letrozole has the strongest current guideline recommendation for PCOS ovulation induction despite lacking a UK product licence for that indication.
Ovulation can return unexpectedly
Lifestyle change, metformin or fluctuating PCOS activity may restore fertility before cycles become predictable, making contraception counselling essential.
More follicles are not better
Excess response during induction increases multiple pregnancy and hyperstimulation risk, so cancellation is a safety success rather than treatment failure.
Common pitfalls
01
Requiring weight loss before offering symptom treatment or appropriate fertility referral.
02
Prescribing combined hormonal contraception without blood pressure, migraine, smoking, thrombosis and interaction assessment.
03
Adding spironolactone or another anti-androgen without reliable contraception and a pregnancy plan.
04
Stopping eflornithine or hormonal treatment after a few weeks because existing hair has not yet changed.
05
Using metformin as the universal opening fertility treatment despite more effective ovulation-induction options.
06
Starting repeated letrozole or clomifene cycles before considering semen, tubal factors and preconception metabolic health.
Practice
Two practice questions
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Question 1 of 2
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Obstetrics and gynaecologyOriginal SBA
Preferred oral ovulation induction
A 30-year-old with PCOS has anovulatory infertility, patent tubes and a partner with normal semen analysis. Which pharmacological option is preferred by the current international PCOS guideline?
Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Combined oral contraception suppresses ovarian androgen production, raises SHBG and produces scheduled endometrial shedding. The international guideline supports its use for irregular cycles or hirsutism, with general population contraceptive guidance determining formulation. Review migraine aura, venous thromboembolism, smoking, blood pressure, age, interacting medicines and postpartum status. Higher-risk cyproterone-containing combinations are not routine opening choices. Progestogen-only contraception and the LNG-IUS protect the endometrium but do not consistently treat hirsutism.
Metformin improves insulin action and is primarily considered for anthropometric and metabolic outcomes, especially in adults with BMI at least 25 kg/m², with individual consideration below that threshold. Start with a low dose with food and increase in 500 mg steps every one to two weeks; modified release can improve gastrointestinal tolerance. Review renal and hepatic safety, pause around acute illness or contrast according to current guidance, and consider vitamin B12 monitoring when risk or symptoms exist. It is not a universal fertility medicine or a licence to ignore cardiovascular care.
Hair treatment requires time and combined methods. Shaving, waxing, depilatory methods, electrolysis and laser or light therapy can be used according to skin and hair type; experienced services reduce pigment complications. Eflornithine slows facial hair growth while used but does not remove existing hair. If at least six months of combined contraception and cosmetic treatment is inadequate, a specialist may add spironolactone or another anti-androgen. Reliable contraception is essential because fetal androgen blockade can harm genital development.
For anovulatory infertility with no other identified factor, the 2023 guideline places letrozole ahead of clomifene because it improves ovulation, pregnancy and live birth outcomes. Letrozole remains off-label for this indication in the UK, so a fertility service should confirm absence of pregnancy, choose the dose, monitor response and define cancellation rules. Metformin alone can improve pregnancy outcomes but is less effective than ovulation agents; clomifene raises multiple-pregnancy risk and may require ultrasound monitoring.
Before repeated induction, assess the whole fertility context: age, duration, semen analysis, sexual history, pregnancy risks and whether tubal testing is appropriate. Gonadotrophins or laparoscopic ovarian surgery can be used after oral induction failure in selected patients; gonadotrophins require low-dose protocols and ultrasound because of multiple pregnancy and ovarian hyperstimulation. IVF is considered when other induction fails or another indication exists. Discuss cumulative chance, burden, costs and stopping points rather than presenting escalation as guaranteed success.
Key points
Agree the dominant goal before treatment: predictable bleeding, contraception, endometrial protection, hirsutism, acne, metabolic health and conception require different choices.
Lifestyle support is recommended for all and should improve health without a single mandated diet or exercise plan; symptom medicines can be offered concurrently rather than withheld until weight changes.
Combined oral contraception can treat irregular cycles and hirsutism when eligible; choose the lowest effective oestrogen dose and progestogen through UK contraceptive safety guidance rather than assuming one pill suits everyone.
When oestrogen is unsuitable or contraception is not wanted, an LNG-IUS, progestogen-only method or periodic oral progestogen can protect the endometrium, but only some options improve androgen symptoms.
Metformin is chiefly used for metabolic outcomes and can assist cycle regulation, particularly when BMI is at least 25 kg/m² or combined contraception is unsuitable; titrate slowly and consider vitamin B12 risk.
Hirsutism improvement takes at least six months. Combine cosmetic hair removal with hormonal treatment; add a specialist anti-androgen only with effective contraception and careful safety review.
The 2023 PCOS guideline recommends letrozole as the preferred pharmacological ovulation-induction option for anovulatory infertility without another factor, but UK use is off-label and belongs in a monitored fertility pathway.
A positive pregnancy test during anti-androgen, retinoid or weight-loss medicine exposure requires prompt specialist medicine and pregnancy advice without abrupt unsafe assumptions.
Severe abdominal pain, rapid distension, vomiting, oliguria, dyspnoea or rapid weight increase during gonadotrophin or assisted-conception treatment suggests ovarian hyperstimulation and needs urgent fertility-unit contact.
Heavy or persistent abnormal bleeding despite cycle treatment requires pregnancy testing and structural or endometrial investigation.
05Ultrasound during stimulated cycles
Why
Count developing follicles, time treatment and limit multiple-pregnancy or hyperstimulation risk.
Interpretation and limitations
Excess follicular response triggers protocol-defined cancellation or modification; a scan is a safety tool, not evidence that more follicles always improve outcome.
2
Use facial eflornithine alongside removal if appropriate, assessing benefit by four months and continuing only while useful.
3For persistent symptoms, seek specialist anti-androgen advice, document effective contraception and monitor drug-specific renal, potassium, hepatic or psychological risks.
03Metabolic treatmentUse metformin for a defined indicationMetabolic risk, dysglycaemia or cycle management makes metformin a shared option.+
1Review renal and hepatic status, gastrointestinal history, pregnancy plans and baseline diet or B12 risks before prescribing.
2Start 500 mg with food and increase in 500 mg increments every one to two weeks toward the tolerated agreed dose, considering modified release for adverse effects.
3Measure success against the original goal and continue independent glycaemic, blood pressure and lipid surveillance rather than using metformin as a surrogate.
04FertilityInduce ovulation through a monitored sequenceAnovulatory infertility is confirmed and pregnancy is desired.+
1Optimise preconception health, complete couple-based assessment and decide whether tubal testing is needed before repeated treatment.
2PreferredOffer monitored specialist letrozole as the preferred oral induction option under current PCOS guidance, explaining off-label UK use and excluding pregnancy.
3EscalationEscalate unsuccessful treatment to clomifene or metformin combinations, gonadotrophins, selected ovarian surgery or IVF according to response, other factors and patient preference.
Temporarily inhibits aromatase to raise endogenous FSH and induce monofollicular ovulation in anovulatory PCOS infertility.
Letrozole for ovulation induction
A common specialist protocol gives 2.5 mg orally once daily for five days from cycle day 2–5, with protocol-led escalation and ultrasound or ovulation monitoring.
Use is off-label for ovulation induction in the UK; exclude pregnancy, assess other fertility factors and apply monitoring and cancellation rules for response and multiple pregnancy.
Provides episodic progestogen exposure and withdrawal shedding when contraception or continuous cycle suppression is not required.
Oral medroxyprogesterone acetate
For secondary amenorrhoea the SmPC permits 2.5–10 mg orally daily for 5–10 days beginning on the assumed or calculated cycle day 16–21; PCOS repeat timing is set by the clinician's endometrial-protection plan.
Exclude pregnancy and assess abnormal bleeding first; it neither provides reliable contraception nor restores ovulation. The SmPC contraindicates known, past or suspected breast cancer, previous idiopathic or current venous thromboembolism, active or recent arterial thromboembolic disease, unresolved liver disease and porphyria.
Assess semen and consider tubal factors before or alongside ovulation induction; gonadotrophins, ovarian drilling and IVF are escalation options rather than substitutes for a complete couple-based assessment.