Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Primary ovarian insufficiency
Obstetrics and gynaecology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Recognise associated adrenal failure
POI with vomiting, abdominal pain, hypotension, hypoglycaemia, hyponatraemia, hyperkalaemia or hyperpigmentation may be part of autoimmune adrenal insufficiency and can progress to adrenal crisis.
Action: Check observations, glucose, electrolytes and cortisol without delaying emergency hydrocortisone and fluid treatment when adrenal crisis is clinically suspected, then involve endocrinology urgently.
Overview
Confirm primary ovarian insufficiency before age 40, investigate genetic and autoimmune causes sensitively, replace sex steroids safely, and address bone, cardiovascular, fertility and psychological consequences.
Primary ovarian insufficiency describes loss or major disturbance of ovarian follicular activity before 40. The word insufficiency is deliberate: ovarian function can fluctuate, bleeding may recur and spontaneous ovulation remains possible. Presentation ranges from new oligomenorrhoea to established amenorrhoea, vasomotor symptoms, sleep disturbance, vaginal dryness, low libido or infertility. Ask about pregnancy possibility, age at menarche, family history, autoimmune disease, pelvic surgery, chemotherapy, radiotherapy, infections and genetic features.
The UK diagnostic standard and the newer international standard are not identical. NICE NG23, still current after its April 2026 update, requires compatible symptoms with elevated FSH on two samples taken four to six weeks apart and states that a single test should not establish POI. The 2025 international evidence-based guideline instead accepts disordered cycles for at least four months with FSH above 25 IU/L, repeating after four to six weeks only when uncertainty exists. In NHS practice use NICE unless the responsible specialist service has adopted a documented alternative; never blend the rules invisibly.
Aetiology
01
Genetic ovarian dysfunction
Turner variants, FMR1 premutation and other chromosomal or monogenic conditions disrupt follicle formation, maintenance or accelerated depletion.
02
Autoimmune follicular injury
Immune-mediated ovarian dysfunction can occur alone or with adrenal, thyroid and other autoimmune disease, although a definitive ovarian antibody test is lacking.
03
Iatrogenic follicle loss
Oophorectomy, alkylating chemotherapy and ovarian radiotherapy can abruptly remove follicles or accelerate depletion according to dose, field and baseline reserve.
04
Unexplained insufficiency
Many spontaneous cases have no identified cause after appropriate evaluation, which should be stated honestly rather than attributed to stress or behaviour.
Pathophysiology
1
Follicular activity declines
Too few responsive follicles or impaired follicle function reduces ovarian oestradiol, inhibin and predictable ovulation before the expected age.
2
Negative feedback is lost
Falling oestradiol and inhibin remove hypothalamic-pituitary restraint, allowing circulating FSH to rise into a persistent hypergonadotrophic pattern.
3
Oestrogen-sensitive tissues change
Sustained deficiency affects thermoregulation, genital epithelium, bone remodelling, vascular function, sleep and sexual wellbeing across years.
4
Residual function fluctuates
Remaining follicles may respond unpredictably, producing intermittent oestradiol, bleeding or ovulation despite a previously confirmed biochemical diagnosis.
Clinical features and red flags
Menstrual change before forty
New oligomenorrhoea or amenorrhoea before age 40, particularly with vasomotor or genitourinary symptoms, should prompt pregnancy exclusion and POI assessment.
Hypergonadotrophic hypogonadism
Raised FSH with low oestradiol reflects loss of ovarian negative feedback and distinguishes ovarian insufficiency from hypothalamic or pituitary suppression.
Iatrogenic context
Bilateral oophorectomy, gonadotoxic chemotherapy or pelvic radiotherapy may cause abrupt or delayed ovarian dysfunction and creates an early fertility-preservation and replacement discussion.
Genetic phenotype
Short stature, dysmorphism, primary amenorrhoea, family POI, learning history or Fragile-X relatives increases the value of genetics-led assessment.
Autoimmune association
Thyroid disease, vitiligo, type 1 diabetes or adrenal symptoms can accompany autoimmune POI, although ovarian autoantibody panels are not routine diagnostic tests.
Red flags requiring action
Collapse, hypotension, recurrent vomiting, abdominal pain, hypoglycaemia or electrolyte disturbance with autoimmune features requires urgent assessment for adrenal crisis.
A positive pregnancy test with pain or bleeding still requires ectopic-pregnancy assessment because intermittent ovulation can occur after a POI diagnosis.
Investigations
01Pregnancy test and repeated FSHFirst step
Why
Exclude pregnancy and biochemically confirm the UK NICE diagnosis in a person under 40.
Interpretation and limitations
NICE requires raised FSH on two samples four to six weeks apart with compatible symptoms; review exogenous hormones and do not diagnose from one isolated value.
02Oestradiol and pelvic ultrasound
Why
Support assessment of oestrogen exposure and answer selected anatomical or bleeding questions.
Interpretation and limitations
Low oestradiol supports hypo-oestrogenism but is not the sole diagnostic criterion; normal ovarian volume or visible follicles does not exclude fluctuating POI.
03Chromosomal analysis and FMR1 testing
Why
Identify genetic causes with implications for cardiovascular care, fertility and relatives.
Interpretation and limitations
Testing follows consent and genetic counselling; Turner variants and FMR1 premutation lead to distinct personal and family pathways rather than a generic abnormal result.
04TSH and 21-hydroxylase antibodies
Why
Detect associated thyroid dysfunction and autoimmune adrenal risk in non-iatrogenic unexplained POI.
Interpretation and limitations
Treat abnormal thyroid function normally; positive adrenal antibodies require endocrinology assessment, while a negative result is not repeated routinely without new symptoms.
Differential diagnosis
01
Functional hypothalamic amenorrhoea
Energy deficit, exercise or stress produces low oestradiol with low or inappropriately normal FSH rather than loss of ovarian feedback.
02
Hyperprolactinaemia
Prolactin excess suppresses GnRH and causes central hypogonadism, often with medicine, galactorrhoea or pituitary clues and non-raised FSH.
03
Pregnancy or hormonal treatment
Pregnancy and exogenous hormones alter bleeding and gonadotrophins, so both must be resolved before biochemical classification.
04
Müllerian or outflow difference
Primary amenorrhoea with normal breast development and uterine absence or obstruction reflects anatomy rather than depleted ovarian follicles.
Management
01ConfirmationApply an explicit diagnostic standardFirst stepA person younger than 40 has disordered cycles or oestrogen-deficiency symptoms.+
1Exclude pregnancy, document at least the relevant duration of cycle change and review contraception, HRT, surgery and gonadotoxic treatment.
2Under NICE, demonstrate raised FSH twice four to six weeks apart with compatible symptoms; refer when results or treatment effects make classification uncertain.
3Explain the diagnosis sensitively and arrange early symptom, fertility, bone and cardiovascular care rather than waiting for every causal test.
02Cause assessmentInvestigate findings that change carePOI is confirmed without a clear bilateral-oophorectomy or gonadotoxic explanation.+
1Offer chromosomal analysis and FMR1 premutation testing through appropriate consent and genetic counselling.
Complications
01
Low bone density
Early prolonged oestrogen deficiency impairs peak bone mass or accelerates remodelling, increasing osteopenia, osteoporosis and later fracture risk.
02
Cardiovascular harm
Untreated early oestrogen loss is associated with adverse vascular and metabolic outcomes, compounded by smoking, hypertension, diabetes and dyslipidaemia.
03
Infertility and uncertainty
Reduced and unpredictable ovulation makes spontaneous conception less likely while creating difficult decisions about contraception, donor eggs and timing.
04
Psychosexual morbidity
Unexpected diagnosis, vaginal symptoms, altered libido, fertility grief and genetic implications can affect identity, relationships and mental health.
Monitoring and follow-up
Review symptoms, adherence, blood pressure, bleeding, contraception and treatment preference after initiation and at least annually, without using routine serum oestradiol as the sole adequacy measure.
Record baseline DXA and repeat after one to three years when low bone density, fracture or inadequate replacement requires response assessment; normal density with adequate therapy rarely needs frequent scanning.
Monitor thyroid function about every five years or sooner with symptoms under the international guideline, and do not repeat negative 21-hydroxylase antibodies without new adrenal concern.
Reassess cardiovascular factors including smoking, blood pressure, lipids, glycaemia, activity and nutrition, with specialist surveillance for Turner-related aortic disease.
Revisit fertility and contraception because ovarian activity can fluctuate, and provide early pregnancy assessment after a positive test.
Special situations
NICE and international criteria differ
Current NICE still requires two raised FSH samples, whereas the 2025 international guideline accepts one clear value and repeats only for uncertainty.
POI is not sterility
Intermittent ovarian function means a patient may ovulate, bleed or conceive unexpectedly, although overall spontaneous conception probability is substantially reduced.
AMH is not the diagnosis
A low AMH reflects follicle quantity but neither replaces the NICE FSH criterion nor proves that all intermittent ovarian activity has ended.
Replacement is preventive care
In a young patient, physiological hormone therapy replaces a deficiency and supports long-term health rather than merely treating hot flushes.
Genetics changes relatives' care
A Turner variant or FMR1 premutation affects counselling, surveillance and family testing, so results should be delivered through a genetics-informed pathway.
Common pitfalls
01
Diagnosing POI from one raised FSH in UK practice without acknowledging the current NICE two-sample criterion.
02
Using a low AMH alone to label a young person with irreversible ovarian failure.
03
Prescribing oestrogen without endometrial progestogen when a uterus is present.
04
Stopping hormone replacement when symptoms settle even though the person remains far younger than natural menopause age.
05
Telling a patient that pregnancy is impossible or that HRT provides contraception.
06
Offering unproven ovarian rejuvenation procedures as established alternatives to reproductive-medicine counselling.
Practice
Two practice questions
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Question 1 of 2
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Obstetrics and gynaecologyOriginal SBA
Current UK POI confirmation
A 34-year-old has five months of amenorrhoea, hot flushes, a negative pregnancy test and one raised FSH result. What next step best follows current NICE guidance?
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.
Pregnancy must be excluded, and hormonal contraception or HRT can conceal cycle pattern and lower FSH. Low oestradiol supports hypo-oestrogenism but does not replace the diagnostic FSH pattern. AMH may help when uncertainty persists in the newer international pathway, yet NICE advises against routine AMH for diagnosis and a low value alone is not POI. Bilateral oophorectomy before 40 establishes iatrogenic POI without biochemical proof.
Most spontaneous cases remain unexplained, but identifying a cause can change care for the patient and relatives. After counselling, non-iatrogenic POI usually prompts chromosomal analysis and FMR1 premutation testing. A 45,X or mosaic Turner result changes cardiovascular, renal and pregnancy assessment; an FMR1 premutation has reproductive and family implications. Screen for 21-hydroxylase antibodies when the cause is unknown and refer a positive result to endocrinology. Check TSH, but the 2025 guideline does not recommend routine thyroid-peroxidase antibodies because background positivity is common.
Oestrogen deficiency before the natural menopause affects symptoms, bone, cardiovascular markers, sexual health and possibly cognition. Offer replacement unless contraindicated and continue to about the usual menopausal age, then reconsider using ordinary menopause principles. HRT may have more favourable blood-pressure and bone effects than a combined pill, while the combined pill provides contraception and may be preferred. Use physiological oestradiol doses; if a uterus is present, adequate cyclic or continuous progestogen is essential to prevent endometrial hyperplasia.
Baseline DXA is recommended by the 2025 international guideline, particularly because delayed diagnosis, under-replacement, fracture, low weight or other bone risks are common. Interpret results with age-appropriate Z-scores in younger adults. If bone density is normal and systemic hormone replacement is adequate, frequent repeat scanning has little value; low bone density, osteoporosis or poor adherence usually warrants repeat DXA after one to three years. Investigate other secondary bone causes rather than escalating calcium alone.
Fertility conversations need precise, compassionate language. POI reduces the probability of spontaneous conception but does not make it impossible, and HRT does not suppress every ovulation. There is no proven medicine, platelet-rich plasma or stem-cell procedure that reliably restores ovarian activity. Donor-oocyte IVF is an established route to pregnancy, while ovarian tissue or oocyte preservation is relevant mainly before gonadotoxic treatment rather than after established follicle loss. Offer psychological, sexual and genetic support without forcing immediate decisions.
Key points
POI means loss or marked fluctuation of ovarian activity before age 40, presenting with irregular or absent cycles, oestrogen-deficiency symptoms or infertility; it is not synonymous with irreversible zero ovarian function.
Exclude pregnancy and treatment effects. Current NICE NG23 diagnoses POI from symptoms and elevated FSH on two samples four to six weeks apart, and advises against diagnosis from one test or routine AMH.
The newer 2025 international guideline uses at least four months of disordered cycles plus FSH above 25 IU/L, repeating FSH only if uncertainty remains; follow the current NHS or specialist pathway and document which criterion is applied.
For non-iatrogenic POI, specialist assessment commonly includes chromosomal analysis, FMR1 premutation testing with genetic counselling, TSH and 21-hydroxylase antibodies when the cause is unknown.
Offer sex-steroid replacement with HRT or an eligible combined hormonal contraceptive and continue until at least the usual age of natural menopause unless contraindicated; protect the endometrium whenever a uterus is present.
HRT is not contraception. Intermittent ovulation and occasional spontaneous conception can occur, so discuss pregnancy testing, contraception and fertility goals explicitly.
Short stature, webbed neck, lymphoedema history, cardiac signs or a Turner-pattern karyotype requires specialist cardiovascular and aortic assessment before pregnancy treatment.
New neurological symptoms, galactorrhoea or low rather than raised gonadotrophins should trigger diagnostic reconsideration for central disease.
Severe distress, suicidal thoughts or acute crisis after an unexpected fertility diagnosis needs urgent psychological or mental-health support.
05Dual-energy X-ray absorptiometry
Why
Measure baseline bone density and guide follow-up when prolonged oestrogen deficiency may have reduced skeletal strength.
Interpretation and limitations
Use age-appropriate interpretation, consider height and other secondary causes, and repeat in one to three years when low density or inadequate replacement needs response assessment.
06Cardiovascular risk assessment
Why
Establish blood pressure, smoking, glucose and lipid factors that interact with early oestrogen deficiency and treatment choice.
Interpretation and limitations
Manage abnormalities through standard risk pathways; a Turner diagnosis additionally requires specialist structural cardiac and aortic imaging before pregnancy.
2
Check TSH and 21-hydroxylase antibodies in unexplained disease, referring positive adrenal antibodies or symptoms to endocrinology.
3Use phenotype and history to select further autoimmune, metabolic or specialist tests and avoid unsupported commercial ovarian-autoantibody panels.
03ReplacementRestore physiological sex-steroid exposurePOI is established and systemic sex steroids are not contraindicated.+
1Choose physiological HRT or an eligible combined hormonal contraceptive by symptom, contraception, vascular risk, uterine status and preference.
2Add adequate cyclic or continuous progestogen whenever a uterus is present and investigate unscheduled bleeding according to the current HRT pathway.
3Continue to at least the usual natural-menopause age, checking adherence and adjusting dose, route and local vaginal treatment to symptoms and health goals.
04Fertility and pregnancyPlan around intermittent ovarian activityThe patient wants pregnancy now or wishes to understand future options.+
1Explain that intermittent spontaneous ovulation can occur but cannot be predicted or reliably restored by current medicines.
2Refer to reproductive medicine for age-sensitive discussion of donor-oocyte IVF, prior stored gametes or tissue and the evidence limits of experimental interventions.
3Complete preconception medical assessment, including specialist aortic and cardiac review for Turner syndrome, before assisted conception or pregnancy.
Key medicines and prescribing safety4 treatments · regimens, roles and cautions+
Replaces deficient oestrogen to treat symptoms and support bone, cardiovascular, genitourinary and sexual health.
Transdermal 17β-oestradiol
Use a physiological replacement regimen, commonly a 100 microgram/24-hour patch changed twice weekly, with dose adjusted by symptoms, tolerability and specialist goals until natural-menopause age.
Add adequate progestogen with an intact uterus; review unexplained bleeding, hormone-sensitive cancer, thrombosis and liver disease, while recognising transdermal oestradiol has lower thrombotic impact than oral therapy.
Opposes oestrogen at the endometrium and creates predictable withdrawal bleeding in a uterus-bearing patient.
Micronised progesterone
With cyclic oestradiol, a common regimen is 200 mg orally at bedtime for 12–14 days of each 28-day cycle; a continuous regimen may use 100 mg nightly after specialist review.
Review sedation, dizziness and bleeding pattern, use adequate duration for the oestrogen dose, and investigate persistent or late-onset unscheduled bleeding rather than simply increasing courses.
Provides contraception, ovarian suppression, symptom control and bone-protective sex-steroid exposure as an alternative to HRT.
Combined hormonal contraception
Use one licensed oral tablet daily or the selected patch or ring schedule according to UK contraceptive guidance, continuing without an unnecessary monthly hormone-free interval when clinically appropriate.
Check migraine aura, smoking, blood pressure, venous and arterial thrombosis, liver disease and interacting medicines; HRT may offer more physiological replacement for some patients.
Assess bone health with DXA at diagnosis under current international guidance, support adequate calcium, vitamin D and weight-bearing activity, and avoid substituting supplements for adequate oestrogen replacement.
No treatment reliably restores depleted ovarian activity; reproductive-medicine discussion includes unpredictable spontaneous ovulation, donor-oocyte conception and options shaped by age, previous treatment and personal values.
Treats vaginal dryness, dyspareunia and urinary symptoms and can be added when systemic replacement is insufficient locally.
Vaginal oestrogen
Use the chosen licensed pessary, tablet, cream or ring loading schedule followed by its maintenance regimen, continuing as needed with periodic clinical review.
It does not replace systemic bone protection in POI; investigate unexplained bleeding and seek specialist advice for hormone-sensitive cancer or persistent symptoms.