PCOS / PMOS glossary
Some terms come up repeatedly in appointments, blood test results, and reading about PCOS / PMOS. This glossary explains the 30 most common — to help you make sense of your results and prepare your questions, not to self-diagnose.
A marker of ovarian follicular reserve, often elevated in PCOS. A high AMH does not mean infertility.
Hormones present in all people, sometimes in excess in PCOS. An excess can cause acne, hirsutism, and hair loss.
One of the 3 diagnostic criteria of PCOS. Can be clinical (visible symptoms) or biochemical (elevated blood levels).
Insulin resistance is common in PCOS (35–80%). It can amplify ovarian androgen production.
An index calculated from fasting glucose and insulin. Thresholds vary — always interpret with your doctor.
One of the 3 Rotterdam criteria. Presents as long or absent cycles. The leading cause of anovulatory infertility in PCOS.
A transport protein for sex hormones. Often low in PCOS, which increases the free (active) fraction of androgens.
Adrenal androgen. Elevated in ~20-30% of PCOS. Used to differentiate from adrenal tumors (>800 µg/dL suspicious).
Biochemical criterion for hyperandrogenism. Free testosterone is more relevant than total in PCOS.
LH/FSH ratio often >2:1 in PCOS. Elevated LH hyperstimulates theca cells, increasing androgen production.
Often low-normal in PCOS. Used to monitor follicular stimulation and assess endometrial preparation.
A day-21 level ≥16 nmol/L confirms ovulation. Often low in anovulatory PCOS.
Key differential: hyperprolactinemia can mimic PCOS symptoms. Routine testing in initial PCOS workup.
Mandatory screening in PCOS workup: Hashimoto's thyroiditis is 5-10× more prevalent in PCOS.
Excludes non-classic congenital adrenal hyperplasia (CAH), the main differential diagnosis for PCOS.
Often elevated in PCOS (reflects the large antral follicle pool). Suppresses FSH secretion.
Differential with Cushing's syndrome. Dexamethasone suppression test if clinical suspicion arises.
Normal <5.6 mmol/L. Insufficient alone to screen for insulin resistance in PCOS — OGTT preferred.
Reflects 3-month average blood glucose. Normal <5.7%. Recommended annually in PCOS with metabolic risk.
Gold standard for insulin resistance in PCOS. 75g oral glucose, measurements at T0/T60/T120 minutes.
Used with fasting glucose to calculate HOMA-IR. Normal <10 mU/L fasting.
Atherogenic dyslipidemia common in PCOS: high TG, low HDL, small dense LDL. Annual panel recommended.
Rotterdam criterion 3: ≥20 follicles 2-9mm per ovary or ovarian volume ≥10 mL (updated ESHRE 2023).
Sum of 2-9mm follicles in both ovaries. PCOS threshold ≥20 (ESHRE 2023). Also an ovarian reserve marker.
Score 0-36 across 9 body areas. Threshold >4-6 depending on ethnicity. Rotterdam clinical hyperandrogenism criterion.
Hyperpigmented velvety skin thickening on neck and armpits. Strong visual marker of hyperinsulinemia in PCOS.
International standard: 2 of 3 criteria (oligo-anovulation, hyperandrogenism, PCOM) after excluding differentials.
4 phenotypes based on which criteria are present. Phenotype D (no hyperandrogenism) is often underdiagnosed.
More restrictive alternatives. NIH 1990 excludes phenotypes C and D; ESHRE 2023 is the current standard.
Non-classic CAH, Cushing syndrome, hyperprolactinemia, androgen-secreting tumors, thyroid disease, POI.
Go further: which tests to discuss · understand my blood results · insulin resistance