Gynecology & Endocrinology & Family Medicine
Polycystic ovary syndrome (PCOS)
Polycystic ovary syndrome (PCOS) — also known as PCOS in English (Polycystic Ovary Syndrome) — is the most common endocrine disorder and cause of chronic anovulation in women of reproductive age, affecting 5 to 15% of women depending on the diagnostic criteria used, and representing the leading cause of anovulatory infertility worldwide. PCOS is a heterogeneous syndrome characterized by the classic triad of hyperandrogenism (clinical: hirsutism + acne + androgenetic alopecia + or biochemical: elevated free testosterone) + ovulatory dysfunction (oligo-anovulation → irregular, infrequent, or absent menstrual cycles) + and a polycystic appearance of the ovaries on ultrasound (polycystic ovarian morphology—POM: ≥ 20 follicles of 2–9 mm per ovary or ovarian volume ≥ 10 mL)—of which at least two must be present according to the 2003 Rotterdam criteria (the most widely used), after exclusion of other causes (congenital adrenal hyperplasia + Cushing’s syndrome + androgen-secreting tumor + hypothyroidism + hyperprolactinemia). Its central pathophysiology is based on insulin resistance—present in 50 to 70% of women with PCOS — which leads to compensatory hyperinsulinemia stimulating ovarian and adrenal androgen production + disruption of folliculogenesis + and inhibition of hepatic secretion of SHBG (sex hormone-binding globulin), increasing the biologically active free fraction of androgens. The long-term consequences of PCOS extend beyond the reproductive sphere: increased risks of type 2 diabetes (× 3–7) + metabolic syndrome + hypertension + non-alcoholic fatty liver disease + endometrial cancer (due to relative hyperestrogenism in chronic anovulation—unprogestinized endometrium) + and potentially long-term cardiovascular morbidity, justifying regular metabolic monitoring beyond fertility management.
Rotterdam Criteria 2003 (2 out of 3 criteria)
- Criterion 1 – Ovulatory Dysfunction (oligo-anovulation): oligomenorrhea (cycles > 35 days) + or amenorrhea (> 90 days of absent periods) + or irregular cycles < 8 cycles per year + confirm with serum progesterone measurement in the mid-luteal phase (< 5 nmol/L = anovulatory cycle) + basal body temperature chart
- Criterion 2 – Hyperandrogenism: Clinical → Hirsutism (Ferriman-Gallwey score ≥ 8: dark, coarse hair on chin + upper lip + cheeks + chest + abdomen + back + thighs) + or recurrent inflammatory acne + or androgenetic alopecia (Hamilton-Ludwig type) + Biochemical → elevated total or free testosterone + or elevated free androgen index (FAI = total testosterone / SHBG × 100) + elevated DHEA-S (adrenal component)
- Criterion 3 — Polycystic ovarian morphology (PCOM) on pelvic ultrasound: ≥ 20 follicles measuring 2–9 mm per ovary (on one section) OR ovarian volume ≥ 10 mL (with no cysts or dominant follicles) + string of pearls appearance + the new 2018 thresholds recommend ≥ 20 follicles/ovary on a high-resolution probe (≥ 8 MHz)
- Mandatory exclusions before PCOS diagnosis: Pregnancy + non-classic congenital adrenal hyperplasia (basal 17-OHP + Synacthen test) + Cushing's syndrome (urinary cortisol + dexamethasone suppression test) + androgen-secreting tumor (very high testosterone > 5–6 nmol/L) + hypothyroidism (TSH) + hyperprolactinemia (prolactin)
PCOS Phenotypes (2012 Classification)
- Phenotype A (classic - most severe): Hyperandrogenism + ovulatory dysfunction + PCOS → maximal insulin resistance + high metabolic risk
- Phenotype B: Hyperandrogenism + ovulatory dysfunction + WITHOUT PCOS → metabolically similar to phenotype A
- Phenotype C (ovulatory): hyperandrogenism + PCOS + regular cycles → relatively preserved metabolism
- Phenotype D (non-hyperandrogenic): Ovulatory dysfunction + PCOS + WITHOUT hyperandrogenism → mildest form + lower metabolic risk + some experts question this phenotype as true PCOS
Initial biological assessment
| Parameter | Threshold / Interpretation | Objective |
|---|---|---|
| Total testosterone + SHBG → FAI | Total testosterone > 2.5 nmol/L (or per lab) + IAL > 5 = biochemical hyperandrogenism | Confirm biochemical hyperandrogenism + if testosterone > 5–6 nmol/L → exclude androgen-secreting tumor |
| TSH | Normal 0.4-4 mIU/L | Exclude hypothyroidism (a cause of menstrual irregularities + hyperandrogenism) |
| Prolactin | < 25 µg/L (or as per laboratory) | Rule out hyperprolactinemia (a cause of anovulation) |
| 17-OH progesterone baseline | < 6 nmol/L (morning + follicular phase) | Exclude nonclassic congenital adrenal hyperplasia (cryptic form) → if > 6 nmol/L → Synacthen test |
| FSH + LH | LH/FSH ratio often > 2–3 in PCOS, but not specific + low-normal FSH | Exclude premature ovarian insufficiency (high FSH) + useful if fertility workup |
| Fasting blood glucose + insulinemia + OGTT if diabetes suspected | Fasting blood glucose ≥ 7 mmol/L = diabetes + 5.6–6.9 mmol/L = prediabetes + HOMA-IR (blood glucose × insulin level / 22.5) > 2.5–3 = insulin resistance | Screening for type 2 diabetes + insulin resistance → guides the indication of metformin |
| Lipid profile | LDL + HDL + TG + CT | Screen for dyslipidemia associated with PCOS (hypertriglyceridemia + low HDL) |
Treatment according to clinical objective
- Weight loss (all forms with overweight): 5–10% weight loss → restoration of spontaneous ovulation in 55–60% of cases in obese women + reduction in hyperandrogenism + improvement in insulin resistance + first-line treatment to be prescribed before any pharmacotherapy + low-calorie diet + aerobic exercise 150 min/week + referral to a nutritionist
- Regulation of menstrual cycles (without desire for pregnancy): Combined oral contraceptives (COCs) with anti-androgenic activity → cyproterone acetate + ethinylestradiol (Diane-35®) + or drospirenone + EE (Yasmin® + Yaz®) + or desogestrel + EE → cycle regulation + reduction of hirsutism and acne + endometrial protection (prevention of endometrial hyperplasia due to chronic anovulation) + cyclic progestin (medroxyprogesterone acetate 10 mg × 10–14 days/month) if COCs are contraindicated
- Hirsutism and acne (anti-androgenic treatment): spironolactone 50–200 mg/day (antiandrogen + most effective for hirsutism + acne + simultaneous contraception mandatory due to risk of feminization of a male fetus) + finasteride 2.5–5 mg/day (5α-reductase inhibitor - less used in women) + cyproterone acetate (in Diane-35) + usual acne treatment + laser hair removal for established hirsutism (does not treat the cause)
- Insulin resistance and metabolic prevention: Metformin 500–2,500 mg/day (biguanide + reduced insulin resistance + improved ovulation + modest reduction in hyperandrogenism + mild weight loss + prevention of type 2 diabetes → indicated if carbohydrate intolerance + or PCOS phenotypes A/B with documented insulin resistance) + GLP-1 agonists (semaglutide + liraglutide) if obesity + PCOS + severe insulin resistance (very promising emerging data)
- Ovulation induction (desire for pregnancy): letrozole 2.5–7.5 mg/day on days 3–7 of the cycle (aromatase inhibitor — superior to clomiphene according to the 2014 NICHD study — live birth rate 27.5% for % vs. 19.1% for %) + clomiphene citrate 50–150 mg/day on days 3–7 (historical first-line alternative but inferior to letrozole) + concomitant metformin improves ovulation rates + injectable gonadotropins (recombinant FSH) if oral ovulation inducers fail + IVF if treatment fails or for specific indications
ℙ️
Letrozole (Femara®) has replaced clomiphene as the first-line ovulation inducer for PCOS since the publication of the NICHD study in 2014 (Legro et al.) — higher live birth rates (27.5 % vs. 19.1 % per cycle) + fewer cases of ovarian hyperstimulation syndrome + better monofolliculogenesis (fewer multiple pregnancies). Although letrozole is not officially approved by Health Canada for ovulation induction (off-label use), it is widely used and recommended by professional societies (SOGC + ASRM) as a first-line treatment for PCOS.
Long-term surveillance — metabolic risks
- Type 2 diabetes screening: Fasting blood glucose + HbA1c every 1–3 years depending on risk factors + OGTT if prediabetes
- Endometrial cancer: Chronic anovulation → hyperestrogenism without progestogen → endometrial hyperplasia → endometrial adenocarcinoma + risk × 2–3 + any abnormal bleeding → endometrial ultrasound + biopsy if endometrium > 12 mm
- Cardiovascular assessment Blood pressure + lipids + blood sugar + BMI + waist circumference annually + smoking cessation + physical exercise
- Mental health Anxiety + depression + altered body image → frequent in PCOS → screening and psychological support if necessary
Medical consultation recommended
Consult a doctor if the following symptoms are present: very irregular menstrual cycles (fewer than 8 cycles per year) + significant hirsutism + persistent acne resistant to usual treatments + or difficulty conceiving after 6-12 months of unprotected intercourse. These signs suggest PCOS, requiring a complete hormonal assessment + a pelvic ultrasound + and management tailored to the objective (cycle regulation + hyperandrogenism treatment + ovulation induction). For the initial assessment of PCOS and the initiation of treatment, Clinique Omicron offers medical consultations at its service points in Quebec and via telemedicine. To make an appointment, visit cliniqueomicron.ca.
Consult at Clinique Omicron
Clinique Omicron's nurse practitioners (NPs) and doctors diagnose PCOS according to the Rotterdam criteria, prescribe a complete hormonal assessment (testosterone + SHBG + TSH + prolactin + 17-OHP + metabolic panel), prescribe a pelvic ultrasound, initiate treatment based on clinical goals (cycle regulation + hirsutism + metformin + ovulation induction with letrozole), perform long-term metabolic monitoring, and refer patients to gynecology-obstetrics and endocrinology for complex cases or in-depth fertility assessments. Consultations are available at several service points across Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
The content of this page is for informational purposes only and does not replace the advice of a doctor or a gynecologist-endocrinologist. PCOS is a heterogeneous syndrome that requires individualized management based on the clinical phenotype + the patient's goals (contraception + fertility + treatment of hyperandrogenism) + the metabolic profile. Letrozole used for ovulation induction is an off-label indication in Canada.
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