PCOS

What is going on underneath

Two processes reinforcing each other:

Insulin resistance. The body's cells respond poorly to insulin, so more is produced. High insulin drives the ovaries to make more testosterone and lowers sex hormone binding globulin, which frees up more testosterone still. This happens in lean women too — it is not simply a consequence of weight.

Disordered hormone signalling. Altered LH release stops follicles maturing and being released. They accumulate, and ovulation becomes irregular or stops.

The result is a cycle: insulin resistance raises androgens, androgens promote central weight gain, and that worsens insulin resistance. Breaking in at any point improves the rest — which is why relatively modest changes can have effects out of proportion to their size.

What contributes

• Genetics — it runs strongly in families. Ask about mothers, sisters and aunts, including anyone with early diabetes or fertility difficulty
• Ethnicity — more common and often more marked in South Asian women, with insulin resistance appearing at a lower body weight
• Weight, which worsens it — but does not cause it. Around one in five women with PCOS is lean, and their diagnosis is frequently delayed because they do not fit the expected picture

What must be excluded before the label is applied

PCOS is a diagnosis of exclusion, and skipping this step is how other conditions get missed for years:

• Thyroid disease — which causes irregular periods and is simple to test
• Raised prolactin — from a pituitary cause or, commonly, from medication
• Non-classical congenital adrenal hyperplasia — which mimics PCOS closely and needs a 17-hydroxyprogesterone level to identify. Genuinely missed
• Cushing's syndrome and androgen-secreting tumours — rare, but suggested by rapid onset, deepening voice or marked virilisation

The long-term risks worth knowing about

• Type 2 diabetes — substantially increased, and screening is recommended regardless of weight
• Gestational diabetes
• Endometrial cancer — increased where periods are very infrequent, because the womb lining is exposed to oestrogen without the regular progesterone that comes after ovulation. This is the most important and least discussed risk, and it is entirely preventable
• Cardiovascular risk factors — raised cholesterol and blood pressure
• Non-alcoholic fatty liver disease

PCOS is diagnosed on history plus blood tests, both of which we can do remotely. A scan is often not needed at all.

The criteria — and where the over-diagnosis happens

Two of three: irregular ovulation, androgen excess, polycystic ovaries on scan.

• If you have irregular periods and clear androgen features, an ultrasound adds nothing and is not required. A great many women are scanned unnecessarily
• Ultrasound should not be used to diagnose PCOS within eight years of your first period. Multifollicular ovaries are normal in adolescence, and using a scan at that age produces a label a young woman may carry — and act on — for life without ever having had the condition
• Around one in five women without PCOS has polycystic-looking ovaries. The appearance alone is not a diagnosis

Blood tests — what we arrange

• Total testosterone and SHBG, to calculate free androgen index — the useful measure. Take these in the morning
• LH, FSH and oestradiol — ideally days two to five of a cycle, or at any time if periods are absent
• Thyroid function and prolactin — to exclude the common mimics
• 17-hydroxyprogesterone, to exclude non-classical congenital adrenal hyperplasia
• HbA1c and lipids — in every woman with PCOS, whatever her weight, and repeated every one to three years
• Liver function where fatty liver is a consideration

Our female hormone panel covers the core set.

Two tests that mislead

• AMH is not a diagnostic test for PCOS, despite being widely sold as one. It is typically raised in PCOS — which also means a high AMH in a woman with PCOS does not mean unusually good fertility, and it is regularly misread that way
• A single testosterone level can be normal in a woman with obvious clinical androgen excess. Visible signs count as evidence in their own right and do not need biochemical confirmation

What needs referral

Pelvic ultrasound where the picture is unclear or bleeding is abnormal, and gynaecology or endocrinology for fertility treatment, resistant symptoms, or anything suggesting a rarer cause — rapid onset of hair growth, voice change or clitoral enlargement, which warrant prompt assessment rather than routine.

What has the strongest evidence

• Resistance training. Muscle improves insulin sensitivity directly, and this has better evidence in PCOS than cardio alone — yet it is rarely what gets recommended. Two or three sessions a week
• Regular activity of any kind, which improves insulin sensitivity independently of any weight change. This matters: the benefit arrives whether or not the scales move
• A 5–10% weight reduction, where weight is a factor, can restore ovulation, regularise cycles and improve androgen symptoms. Genuinely disproportionate returns for the size of the change

Eating

• Lower glycaemic index carbohydrates — wholegrains, pulses, vegetables — which produce a smaller insulin response
• Protein and healthy fat with each meal, which flattens the blood sugar curve
• Regular meals rather than long gaps followed by large ones
• No specific PCOS diet has been shown to be superior, despite the industry built on claiming otherwise. Sustainability beats theoretical optimisation every time
• If food or weight has become a source of distress, say so. Disordered eating is more common in PCOS, and a restrictive plan is the wrong prescription in that situation

Practical measures

• Track your cycles. Knowing how many periods you have a year is what determines whether the lining needs protecting — and it is the question most often not asked
• Sleep properly; poor sleep worsens insulin resistance measurably
• Get assessed for sleep apnoea if you snore or wake unrefreshed — more common in PCOS and rarely looked for in women
• Stop smoking, which compounds the cardiovascular risk
• Vitamin D, commonly low, and worth checking

Hair, honestly

Hirsutism is often the symptom with the greatest impact on daily life, and it is routinely under-treated.

• Laser or IPL is more effective than any cream or tablet, and gives lasting reduction. Best results on dark hair; less effective on fair or grey
• Electrolysis works on any hair colour
• Medication takes six months to show its effect, because hair grows in cycles — do not judge it at eight weeks
• Plucking and waxing are fine and do not make hair grow back thicker, which is a myth

Two things worth holding on to

The "cysts" are not cysts. They are ordinary follicles. Nothing is growing and nothing needs removing.

PCOS does not mean you cannot have children. Most women with it conceive, many without any treatment at all. It may take longer, and the effective treatments exist — but the diagnosis is not the answer to that question.

Do I actually have cysts on my ovaries?

No — and the name is genuinely misleading. What shows on a scan are ordinary immature follicles, the egg sacs every ovary contains, sitting there because ovulation has not been happening regularly. Nothing needs draining or removing, and nothing is growing. Many women are frightened for years by a word chosen badly decades ago.

Can I still have children?

Most women with PCOS do, and many conceive without any treatment. Irregular ovulation can make it take longer and less predictable, but effective treatments exist — letrozole is now first-line for inducing ovulation, and even modest weight loss restores it in many women where weight is a factor. A PCOS diagnosis is not an answer to whether you can have children.

I was told I have PCOS after a scan. Is that right?

Possibly not. A scan alone cannot diagnose PCOS — around one in five women without it have polycystic-looking ovaries, and in the first eight years after periods start, multifollicular ovaries are normal enough that scanning to diagnose PCOS is explicitly not recommended. If your diagnosis rests on imaging alone, or was made in your teens, it is worth reviewing properly.

Why does it matter if I only get two or three periods a year?

This is the most important and least discussed part of PCOS. Without ovulation there is no progesterone to shed the womb lining, so it thickens under oestrogen alone — and over years that raises the risk of endometrial cancer. It is entirely preventable: the combined pill, a progestogen, or the hormonal coil all protect the lining. If you have fewer than about four periods a year, raise it.

Do I have to lose weight to fix this?

Weight loss helps where weight is a factor — 5–10% can restore ovulation and improve symptoms considerably. But it is not the whole story: around one in five women with PCOS is lean, insulin resistance occurs independent of weight, and exercise improves it whether or not the scales move. Being told only to lose weight is incomplete advice, and given how much more common disordered eating is in PCOS, it can do harm.

My AMH was high — does that mean my fertility is excellent?

No, and this is a common and painful misreading. AMH is typically raised in PCOS simply because there are more small follicles, so it reflects the condition rather than superior fertility. It is also not a diagnostic test for PCOS, despite being marketed as one. Ovulation frequency matters far more than that number.

Will metformin sort out my symptoms?

Partly, sometimes. It improves insulin sensitivity, may help cycle regularity, and is genuinely useful where blood sugar is impaired — but its effect on hair growth, acne and weight is modest, and it is frequently oversold. Start at a low dose and build up, or the gut side effects will end it in the first week.

Is there anything worth taking that isn't a prescription?

Inositol has reasonable evidence in PCOS for insulin sensitivity and cycle regularity — the one supplement here that is not simply marketing. Vitamin D is often low and worth checking. Beyond that, most PCOS-branded supplements have little behind them, and no specific diet has been shown to beat another.

Does PCOS go away after the menopause?

The cycle problems resolve, and androgen levels fall gradually, so hair growth and acne often improve. The metabolic side does not go away — diabetes and cardiovascular risk remain higher, so screening continues to matter after the reproductive symptoms have gone.