The question almost everyone is really asking when they get an AMH test is "how many eggs do I have left?" The honest answer: AMH tracks the resting pool of small follicles, so it is a reasonable proxy for ovarian reserve. But the framing slips. Eggs are not coins in a jar that you spend one per month. AMH tells you how the ovary will respond to IVF stimulation, and gives a rough sense of how close menopause might be. It does not tell you whether you can get pregnant naturally next month.
That distinction matters because women with low AMH at 32 are routinely told something panicked when the actual research says the opposite. Multiple large cohorts show that low AMH in a young, regularly cycling woman does not meaningfully reduce monthly natural fecundity. Egg quality, which is driven by age and not by AMH, matters as much or more for spontaneous pregnancy. Low AMH at 32 means a smaller pool, not a closed door.
Where AMH genuinely shines: planning IVF, timing egg-freezing, and supporting a diagnosis of premature ovarian insufficiency or PCOS (high AMH is one of the most reliable lab features). It has overtaken day-3 FSH as the single most useful ovarian reserve marker. It does not change much across the cycle, so timing of the draw is not critical, and one number gives you most of what an antral follicle count gives you.
What AMH measures
AMH originates in granulosa cells of small antral and pre-antral follicles, the follicles waiting to be recruited but not yet selected for that month's cycle. The largest dominant follicle does not produce AMH (production drops as a follicle grows). So AMH is a measure of the standing pool, not the cycle's currently active follicle.
Properties that make AMH valuable:
- Cycle-stable: varies modestly across the menstrual cycle (~10–20%); a single draw any day works.
- Long term tracking: declines slowly and predictably with age. Trend over years is informative.
- Correlates with antral follicle count on transvaginal ultrasound, usually no need for both.
- Suppressed modestly by combined oral contraceptives: typically 20–30% reduction. Worth noting but not enough to abandon the test on the pill.
- Not a measure of egg quality: only quantity. Quality is age-driven and not directly measurable.
AMH is also produced in small amounts by Sertoli cells in the testis. Male AMH is occasionally measured in pediatric workups for ambiguous genitalia and cryptorchidism, but is not part of the adult reproductive workup.
AMH reference ranges
| Grupo demográfico | Bajo | Alto | Unidad |
|---|---|---|---|
| Women under 30 | 2 | 6.8 | ng/mL |
| Women 30–35 | 1.5 | 4.5 | ng/mL |
| Women 35–40 | 1 | 3.5 | ng/mL |
| Women 40–45 | 0.5 | 2.5 | ng/mL |
| Women 45+ | 0 | 1 | ng/mL |
| PCOS-supportive (any age) | 3.5 | 15 | ng/mL |
| Very low reserve / POI | 0 | 0.5 | ng/mL |
Strongly age-dependent. Approximate values (different assays and units exist; ng/mL is most common in the US, pmol/L elsewhere, multiply ng/mL × 7.14 for pmol/L):
- Women under 30: 2.0–6.8 ng/mL.
- Women 30–35: 1.5–4.5 ng/mL.
- Women 35–40: 1.0–3.5 ng/mL.
- Women 40–45: 0.5–2.5 ng/mL.
- Women 45+: <1.0 ng/mL, often undetectable as menopause approaches.
Practical interpretive bands (any age):
- Above 3 ng/mL: high reserve; in younger women may indicate PCOS.
- 1–3 ng/mL: normal reserve.
- 0.5–1 ng/mL: low reserve.
- Below 0.5 ng/mL: very low reserve; significantly reduced response to IVF stimulation expected.
- Below 0.1 ng/mL or undetectable: approaching or in menopause.
What high AMH means
High AMH usually means more follicles in the resting pool. The differential:
- Polycystic ovary syndrome: by far the most common cause of significantly elevated AMH (often 5–10+ ng/mL). The expanded pool of small antral follicles is the underlying biology of the "polycystic" appearance on ultrasound. AMH is increasingly proposed as a diagnostic criterion for PCOS in adults (e.g., AMH >3.5 ng/mL plus hyperandrogenism or oligomenorrhea), though it is not yet formally adopted.
- Naturally high reserve in a young woman: without other PCOS features. Reassuring rather than concerning.
- Granulosa cell tumor: rare ovarian tumor that produces both AMH and inhibin B. AMH may be very high (often 10+ ng/mL) and accompanied by an adnexal mass on imaging.
An isolated high AMH without hyperandrogenism, irregular cycles, or imaging findings does not require treatment, but it does mean exuberant response to ovarian stimulation in IVF, with corresponding ovarian hyperstimulation syndrome risk that warrants careful protocol selection.
What low AMH means
Low AMH means a smaller pool of follicles. Causes:
- Aging: the dominant cause. Expected, predictable.
- Diminished ovarian reserve: low AMH for age. Reduced response to IVF stimulation; possibly earlier menopause.
- Premature ovarian insufficiency (POI): under 40 with very low AMH plus high FSH and amenorrhea.
- Prior chemotherapy or pelvic radiation: gonadotoxic.
- Prior ovarian surgery: removal of ovarian tissue (cyst removal, endometrioma resection) reduces AMH.
- Endometriosis: particularly with endometriomas, lowers AMH.
- BRCA1 carrier status: modest reduction in AMH in some studies.
- Combined oral contraceptive use: 20–30% suppression. Re-test 2–3 months after stopping for an accurate baseline if planning fertility decisions.
- GnRH agonist therapy: leuprolide and similar can transiently lower AMH.
- Smoking: modest but real reduction.
Important: low AMH does not mean infertility. Many women with AMH below 1.0 conceive naturally. AMH predicts how the ovary responds to IVF stimulation; it is a poor predictor of natural pregnancy in the next 6–12 months. Egg quality (age-driven) matters more than reserve for spontaneous conception.
When AMH is most useful, and when it is overrated
Genuinely useful applications:
- IVF planning: AMH predicts oocyte yield and the right stimulation protocol/dose. The single most predictive lab.
- Egg-freezing decisions: quantifies the urgency. Higher AMH = more flexibility; low AMH for age suggests sooner is better.
- POI suspicion: supports diagnosis alongside high FSH and amenorrhea.
- PCOS workup: high AMH supports the diagnosis.
- Pre-chemotherapy assessment: baseline before gonadotoxic treatment.
- Following ovarian surgery: quantifies tissue impact.
Where AMH is misused:
- Predicting natural conception in young women: low AMH at 30 with regular cycles does not reduce monthly natural fecundity meaningfully. Multiple large cohort studies confirm this.
- Predicting menopause timing precisely: AMH gives a rough range (years) but not a date.
- Triggering aggressive intervention based on a single low value: assays vary; repeat before life-altering decisions.
An AMH value should always be paired with age. AMH of 1.0 ng/mL at age 25 is concerning; at age 42, it is unremarkable.
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When to act on AMH
- AMH below 1.0 ng/mL in a woman under 35 wanting future fertility: counsel about timeline and consider egg-freezing discussion.
- AMH above 3.5 ng/mL with hyperandrogenism, irregular cycles, or polycystic ovary morphology: supports PCOS diagnosis; check insulin sensitivity.
- AMH approaching undetectable in a woman under 40: workup for POI: FSH, estradiol, autoimmune screen, fragile X, karyotype.
- Before IVF: AMH is essential for choosing protocol and predicting response.
- Before pelvic surgery for endometrioma: baseline AMH; surgery reduces it.
- Sudden drop in AMH: re-test on a different assay before making decisions; assay variability is real.
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Tests that complete the picture
- FSH: paired ovarian reserve marker; typically high when AMH is very low.
- Estradiol: day 3 estradiol with FSH for reserve, also reflects current follicular activity.
- LH: high LH/FSH ratio supports PCOS in conjunction with high AMH.
- Antral follicle count (ultrasound): correlates with AMH; either suffices for most reserve questions.
- Testosterone and DHEA-S: PCOS workup.
- Prolactin and TSH: common reversible causes of menstrual irregularity.
- Fasting insulin and HbA1c: metabolic context in PCOS.
- Inhibin B: alternative ovarian reserve marker; less commonly used now.