PCOS diagnosis and long-term care

Rotterdam Diagnostic Criteria

Diagnosis requires the presence of at least 2 out of the following 3 features (after excluding mimickers including thyroid disease, hyperprolactinaemia, and non-classic congenital adrenal hyperplasia via serum 17-hydroxyprogesterone):

1. Oligo- or Anovulation: Manifesting as menstrual cycles $> 35\text{ days}$ apart or $< 8\text{ cycles per year}$.
2. Clinical or Biochemical Hyperandrogenism:
   • Clinical: Hirsutism evaluated using the modified Ferriman-Gallwey score (score $\ge 4\text{ to }6$ depending on ethnicity), moderate-to-severe inflammatory acne, or female-pattern androgenic alopecia.
   • Biochemical: Elevated serum total or calculated free testosterone, elevated Free Androgen Index ($FAI = [\text{Total Testosterone (nmol/L)} / \text{SHBG (nmol/L)}] \times 100 > 4.5$), or elevated dehydroepiandrosterone sulphate (DHEAS).
3. Polycystic Ovarian Morphology (PCOM) on Ultrasound:
   • Presence of $\ge 20\text{ follicles per ovary}$ measuring $2\text{ to }9\text{ mm}$ in diameter, and/or an increased ovarian volume $\ge 10\text{ mL}$ in either ovary (using transvaginal transducers $\ge 8\text{ MHz}$, excluding dominant follicles or corpus luteum). Pelvic ultrasound should not be used for diagnosis within 8 years of menarche due to the high frequency of multi-follicular ovaries in normal post-menarchal adolescence.

Long-Term Health Complications

• Insulin Resistance & Type 2 Diabetes: Intrinsic post-receptor insulin signalling defects lead to compensatory hyperinsulinaemia. Insulin acts synergistically with luteinizing hormone (LH) on ovarian theca cells to drive androgen synthesis and suppresses hepatic production of sex hormone-binding globulin (SHBG), augmenting free circulating testosterone. All women with PCOS require a baseline 75 g 2-hour oral glucose tolerance test (OGTT).
• Cardiovascular Disease & Metabolic Syndrome: High prevalence of atherogenic dyslipidaemia (elevated triglycerides, low HDL, elevated small dense LDL) and hypertension.
• Endometrial protection in PCOS: Address prolonged unopposed oestrogen with a suitable progestogen strategy. Cyclic withdrawal bleeding is one option; continuous progestogen or an LNG-IUD may provide protection with amenorrhoea. Four bleeds per year are not mandatory when the endometrium is already protected.

Therapeutic Principles

• Lifestyle Intervention: The cornerstone of therapy. A modest weight reduction of 5% to 10% of total body weight improves insulin sensitivity, lowers circulating androgens, restores spontaneous ovulatory cycles, and enhances fertility.
• Metformin: An oral biguanide ($1000\text{ to }2000\text{ mg}$ daily in divided doses) that improves peripheral insulin sensitivity, reduces hyperinsulinaemia, promotes modest weight loss, and improves menstrual cyclicity.
• Combined Oral Contraceptive Pills: First-line pharmacological management for hirsutism and irregular menses in women not seeking immediate conception. Oestrogen suppresses pituitary LH secretion and stimulates hepatic SHBG production, reducing bioavailable free testosterone, while the progestogen protects the endometrium against hyperplasia.
• Anti-Androgens: Spironolactone ($50\text{ to }200\text{ mg}$ daily) or cyproterone acetate competitively blocks androgen receptors. Must always be co-prescribed with effective contraception due to the risk of feminization of a male fetus.
• Ovulation Induction for Subfertility: Letrozole (an oral aromatase inhibitor, $2.5\text{ to }7.5\text{ mg}$ daily on cycle days 3 to 7) is the first-line agent of choice, achieving significantly higher ovulation and live birth rates than clomiphene citrate with a lower risk of multiple gestations. Second-line treatments include low-dose exogenous gonadotrophins and laparoscopic ovarian drilling.

Clinical comparison: FIGO PALM-COEIN Classification, Diagnostic Features & Interventions

• Polyp: FIGO Code: AUB-P; Distinguishing Pathophysiological / Imaging Hallmark: Intracavitary focal overgrowth with solitary feeding vascular pedicle on Doppler; First-Line Investigation: Transvaginal ultrasound / Saline infusion sonography; Primary Clinical Management: Hysteroscopic polypectomy with histological examination
• Leiomyoma: FIGO Code: AUB-L; Distinguishing Pathophysiological / Imaging Hallmark: Monoclonal myometrial smooth muscle tumour; submucosal (Types 0–2) causes severe bleeding; First-Line Investigation: Transvaginal ultrasound / diagnostic hysteroscopy; Primary Clinical Management: Tranexamic acid, LNG-IUD, GnRH analogues; myomectomy or hysterectomy
• Coagulopathy: FIGO Code: AUB-C; Distinguishing Pathophysiological / Imaging Hallmark: Systemic haemostatic defect (vWD, thrombocytopenia); menorrhagia since menarche; First-Line Investigation: Coagulation panel, vWF antigen, ristocetin cofactor; Primary Clinical Management: Tranexamic acid, desmopressin, hematology consultation
• Ovulatory: FIGO Code: AUB-O; Distinguishing Pathophysiological / Imaging Hallmark: Unopposed oestrogen from chronic anovulation (PCOS, perimenopause); irregular cycles; First-Line Investigation: Serum $\beta$-hCG, TSH, prolactin, androgen profile, OGTT; Primary Clinical Management: Combined oral contraceptives, cyclic progestogens, metformin, letrozole
• Endometrial: FIGO Code: AUB-E; Distinguishing Pathophysiological / Imaging Hallmark: Deficient local endometrial vasoconstrictors ($PGF_{2\alpha}$) and excessive fibrinolysins; First-Line Investigation: Diagnosis of exclusion; normal ovulatory cycles; Primary Clinical Management: Tranexamic acid, NSAIDs, levonorgestrel IUD ($52\text{ mg}$)
• Iatrogenic: FIGO Code: AUB-I; Distinguishing Pathophysiological / Imaging Hallmark: Drug-induced breakthrough bleeding (anticoagulants, copper IUD, implants); First-Line Investigation: Medication review, rule out pelvic infection; Primary Clinical Management: Adjustment of contraceptive regimen, medical haemostatic support
• Not Classified: FIGO Code: AUB-N; Distinguishing Pathophysiological / Imaging Hallmark: Uterine AVM, chronic endometritis, cesarean scar isthmocele; First-Line Investigation: Colour Doppler ultrasound (turbulent high-velocity flow); Primary Clinical Management: Embolisation for AVM (avoid curettage), targeted antibiotic therapy

Current PCOS assessment

In adults, the 2023 international guideline permits AMH as an alternative to ultrasound for defining polycystic ovarian morphology within the diagnostic algorithm, not as a stand-alone screening diagnosis. When ovulatory dysfunction and hyperandrogenism are both present, neither ultrasound nor AMH is needed for diagnosis after alternatives are excluded. Adolescents require both persistent cycle irregularity appropriate to years since menarche and hyperandrogenism; ultrasound and AMH should not be used to diagnose adolescent PCOS. Exclude thyroid disease, hyperprolactinaemia and non-classic congenital adrenal hyperplasia, and assess rapid virilisation for a tumour.

Primary references (checked 7 October 2026): 2023 international PCOS guideline.