Polycystic ovary syndrome is the most common endocrine condition of reproductive age, affecting something like one in eight to one in ten women depending on the criteria used — and it remains substantially underdiagnosed. Many people go years with a collection of apparently unconnected symptoms: irregular periods, acne, unwanted facial hair, weight that will not shift, and difficulty conceiving.
The name is itself misleading. The “cysts” are not pathological cysts at all but rows of small, immature follicles that have stalled partway through development. Understanding that reframing helps explain the whole condition.
What PCOS actually is
PCOS is a disorder of ovulation and androgen balance. Three processes reinforce each other:
- Insulin resistance — present in the majority of people with PCOS regardless of body weight. The pancreas compensates by producing more insulin
- Hyperinsulinaemia — excess insulin acts on the ovary, directly stimulating androgen production, and simultaneously reduces sex hormone-binding globulin (SHBG), raising free testosterone
- Impaired folliculogenesis — the androgen-rich environment stalls follicle development. Follicles grow to a point and stop, producing the characteristic ultrasound appearance and — critically — no ovulation
Because no egg is released, periods become irregular or absent, and fertility is reduced. Because androgens are elevated, acne, hair growth and hair thinning follow.
Signs worth noticing
Menstrual and reproductive
- Cycles longer than 35 days, or fewer than eight periods a year
- Absent periods (amenorrhoea)
- Difficulty conceiving — PCOS is the leading cause of anovulatory infertility
- Spotting or unpredictable bleeding between cycles
Androgen effects
- Acne, particularly along the jawline, chin and lower face, often persisting past the age where it is expected
- Hirsutism — coarse dark hair in a male-pattern distribution: upper lip, chin, chest, abdomen, lower back. This is the most specific sign and it is measured, not guessed, using a scoring system
- Androgenic hair thinning — widening part with a preserved frontal hairline. See our hair loss guide
- Oily skin and greasy hair
Metabolic and skin signs
- Acanthosis nigricans — dark, velvety thickening of the skin at the nape, armpits, groin or under the breasts. A visible marker of insulin resistance
- Skin tags
- Weight gain concentrated around the abdomen, and weight that resists dieting more than expected
- Deepening voice or increased muscle mass — rare, and always requires urgent investigation
Psychological
Depression and anxiety are substantially more common in PCOS, independent of symptom severity — partly the androgen biology, partly the lived experience of a condition that affects appearance and fertility.
How it is diagnosed
There is no single test. The widely used Rotterdam criteria require two of the following three, after other causes have been excluded:
| # | Criterion | How it is assessed |
|---|---|---|
| 1 | Oligo- or anovulation | Cycle history, or progesterone measurement |
| 2 | Clinical or biochemical hyperandrogenism | Hirsutism/acne scoring; total and free testosterone |
| 3 | Polycystic ovarian morphology | Ultrasound: 12 or more follicles of 2–9 mm per ovary, or increased ovarian volume |
Two of three means someone with classic symptoms and normal-looking ovaries still has PCOS, and someone with the ultrasound appearance and regular cycles but no androgen excess does not.
Ultrasound should not be used alone in adolescents — the appearance is normal for several years after menarche.
What must be excluded first
The mimic list matters, because treating the wrong thing wastes years:
- Thyroid dysfunction (TSH)
- Hyperprolactinaemia (prolactin)
- Non-classic congenital adrenal hyperplasia (17-hydroxyprogesterone) — the commonly missed one
- Cushing syndrome if features suggest it
- Androgen-secreting tumour — if androgens are very high or virilisation is rapid
- Primary ovarian insufficiency
The standard metabolic work-up includes fasting glucose and HbA1c, an oral glucose tolerance test (preferred over HbA1c alone in PCOS, because impaired glucose tolerance is more common than HbA1c detects), and a lipid panel.
Treatments that work
There is no cure, so treatment is directed at whichever of the three problems is actually bothering you. Not everyone needs everything.
Lifestyle — the intervention with the broadest effect
The 2023 international evidence-based guideline sets a target of 5–10% body weight loss in those carrying excess weight. This is not about appearance: that degree of loss frequently restores spontaneous ovulation, improves insulin sensitivity, and reduces androgens — often more effectively than medication.
Regular exercise improves insulin resistance independently of weight change, so it should not be framed as only a weight tool. Dietary patterns with the best evidence include Mediterranean-style and DASH eating, and low-glycaemic approaches; no single macronutrient ratio dominates.
Restoring and protecting cycles
- Combined oral contraceptive — regulates bleeding, lowers androgen via SHBG, improves acne. Note that it masks cycles rather than treating the underlying cause, and combined hormonal contraception is not first-line for metabolic risk factors alone
- Cyclic progestogen — for those who cannot or prefer not to use oestrogen. Withdrawal bleeding every few months also protects the endometrium
- Endometrial protection — if periods are absent for more than roughly three to four months, bleeding should be induced. Persistent unopposed oestrogen exposure raises the risk of endometrial hyperplasia, which is one of the genuinely serious long-term risks of untreated PCOS
Hair and acne
- Topical eflornithine for facial hair — requires ongoing use
- Laser or intense pulsed light — effective but needs multiple sessions; works best on dark, coarse hair and less so on grey or blonde
- Electrolysis — the only method that can be described as permanent for individual hairs
- Pharmacological: combined pill, or spironolactone as an anti-androgen (with reliable contraception, as it is teratogenic)
- Expectations: visible improvement from medication takes six to twelve months. Hair already present does not reverse quickly
Insulin resistance and metabolic risk
- Metformin — improves insulin sensitivity, modest weight benefit, and can restore ovulation. Widely used, particularly where glucose handling is abnormal
- Inositol (myo-inositol with D-chiro in a 40:1 ratio) — the guideline gives it a conditional recommendation for metabolic and ovulatory outcomes; the evidence is modest but it is well tolerated
- GLP-1 receptor agonists — increasingly used for weight and metabolic management where indicated, with growing PCOS-specific data
- Bariatric surgery — considered for BMI ≥40, or ≥35 with comorbidity, in appropriate candidates
- Statins and blood pressure management as indicated by the actual lipid and BP results
Fertility
Most people with PCOS do conceive. The sequence is straightforward:
- Letrozole — now the first-line ovulation induction agent, ahead of clomiphene, based on higher live birth rates
- Metformin — as an adjunct, particularly with insulin resistance or clomiphene resistance
- Gonadotrophin injections — second line, with a real risk of multiple pregnancy and ovarian hyperstimulation
- Laparoscopic ovarian drilling — a surgical option where medications fail
- IVF — where the above do not achieve pregnancy
Weight loss before attempting induction meaningfully improves response. This is a case where a delay can improve the outcome rather than merely postponing it.
Long-term risks worth tracking
- Impaired glucose tolerance and type 2 diabetes — risk substantially elevated, and screening should be regular rather than one-off
- Dyslipidaemia and hypertension
- Non-alcoholic fatty liver disease
- Endometrial hyperplasia from unopposed oestrogen
- Obstructive sleep apnoea — prevalence increased independently of weight
- Cardiovascular risk — elevated, though the absolute numbers in younger populations are smaller than the relative figures suggest
When to seek urgent assessment
- Rapid virilisation — fast-deepening voice, clitoromegaly, rapidly progressive male-pattern balding, sudden severe acne. Requires urgent exclusion of an androgen-secreting tumour
- Heavy or prolonged bleeding after prolonged absence of periods
- Pelvic pain — PCOS is not typically painful; new pain has other causes
- Pregnancy with PCOS — increased risks of gestational diabetes, pre-eclampsia and preterm birth warrant specialist care
- Persistent low mood or anxiety — common, treatable, and not an inevitable part of the diagnosis
Frequently asked questions about PCOS
Do I actually have cysts on my ovaries?
Almost certainly not, in the pathological sense. The ultrasound appearance is a row of small arrested follicles — a sign that ovulation is not completing — rather than true ovarian cysts that might rupture or need removal. The name predates ultrasound and has caused decades of unnecessary alarm.
Will I be able to get pregnant?
Most likely, yes. The issue is ovulation, not an inability to carry a pregnancy. Restoring ovulation — through weight management, letrozole, or the steps above — resolves it in the large majority. PCOS is associated with somewhat higher miscarriage and gestational diabetes risk, which is why early obstetric involvement helps.
Is PCOS caused by being overweight?
No, and the framing causes real harm. Thin people get PCOS, and the insulin-resistance pathway operates independently of body size. Excess weight worsens the condition and weight loss improves it, but weight is a modifier rather than the origin. Anyone told their PCOS would resolve “if they just lost weight” has been given an incomplete explanation.
Do I need to take the pill forever?
No. The pill is one tool for one set of symptoms. If cycles are the issue and fertility is not a current goal, cyclic progestogen is an alternative. If the priority is metabolic, that pathway does not involve hormones at all. Treatment should be reviewed annually rather than continued on autopilot.
Can PCOS go away?
The underlying tendency does not disappear, but symptoms frequently improve — particularly after weight loss, and often after pregnancy or with age as ovarian activity declines. Metabolic risks need lifelong attention regardless, because they can persist even when menstrual cycles normalise.
This article is for general information only and is not a substitute for professional medical advice. See our medical disclaimer.
