What the AMH test shows
Anti-Müllerian hormone (AMH) is made by the granulosa cells that surround small, early-stage follicles in the ovary — the preantral and small antral follicles. Because every one of those follicles adds a little AMH to the bloodstream, the level in a blood sample mirrors the size of the pool of eggs a woman has left. That is why AMH is used as a marker of ovarian reserve — an estimate of how many eggs remain, not how good they are. MedlinePlus describes higher AMH as a sign the ovaries hold a larger egg supply, with levels falling toward zero at menopause.
In men and boys the same hormone comes from the Sertoli cells of the testes, where in early fetal life it drives regression of the Müllerian ducts and later reflects testicular function. Male AMH is high throughout childhood and drops at puberty as testosterone rises, so in males the test is used mainly in infants and children — for example to confirm working testicular tissue — rather than in adults, as StatPearls explains.
AMH differs from the hormones it is usually ordered with. FSH is a pituitary signal that climbs only once the ovary is already struggling, and it has to be measured early in the cycle; estradiol comes from the growing follicle and swings across the month. AMH is released directly by the follicle pool and stays relatively steady day to day, so it can be drawn at almost any point in the cycle. Its main limitation is just as important: AMH counts follicles, it does not measure egg quality, and on its own it does not tell you whether you can conceive.
AMH normal range
AMH is reported either in ng/mL (common in the United States) or in pmol/L (used in the UK, Europe and most SI-unit labs). Unlike many blood tests, these two numbers are not interchangeable — to convert ng/mL to pmol/L you multiply by about 7.14 (so 1.0 ng/mL ≈ 7.1 pmol/L). There is no single “normal” value: AMH depends heavily on age and on the assay platform used, and professional bodies stress there is no agreed cut-off for a “low” result, per ASRM.
| Age (women) | Typical orientation, ng/mL | ≈ pmol/L (× 7.14) |
|---|---|---|
| Under 30 | ~2.0–6.8 | ~14–49 |
| 30–34 | ~1.5–4.0 | ~11–29 |
| 35–37 | ~1.1–3.0 | ~8–21 |
| 38–40 | ~0.7–2.0 | ~5–14 |
| 41–45 | ~0.3–1.5 | ~2–11 |
| Postmenopausal | undetectable (≈ 0) | ≈ 0 |
| Men (adult) | low; age-specific in boys | use pediatric range |
As a rough guide, median AMH slips below about 1.2 ng/mL by the mid-thirties. Many clinics read a value above roughly 4 ng/mL as high (a prompt to consider PCOS), around 1.5–4 ng/mL as average, below about 1 ng/mL as diminished reserve, and below 0.5 ng/mL as very low. Treat these as orientation, not diagnosis — the same sample can read differently on different assays, so always compare your result with your own lab’s range and, ideally, track it on one platform. Because AMH is steady across the cycle, it is one of the few hormone tests that does not have to be timed to your period (more on cycle timing).
Why AMH is low
A low AMH is the main reason the test is ordered, and it usually reflects the number of eggs remaining rather than any single disease. Roughly by frequency:
- Age. Reserve falls steadily through the thirties and forties; a lower number at 40 than at 30 is expected biology, not a fault.
- Diminished ovarian reserve (DOR): fewer follicles than expected for age. Its practical value is in fertility treatment, where AMH predicts how many eggs the ovaries will yield during IVF stimulation.
- Primary ovarian insufficiency (POI) / early menopause: a very low AMH together with a high FSH, low estradiol and missed periods before age 40. This matters well beyond fertility — the low estrogen affects bone and heart health — and needs specialist assessment.
- Ovarian surgery (for example removing an endometrioma or cyst) and gonadotoxic chemotherapy or radiation, which can lower AMH sharply.
- Endometriosis, which is associated with lower AMH.
- Hormonal contraception or GnRH-agonist treatment, which can suppress AMH by roughly 15–30% temporarily; the value recovers after stopping and does not reflect a true loss of eggs.
The most important point about a low AMH is what it does not mean. Both ACOG and ASRM are explicit that AMH does not predict natural fertility or time to pregnancy in women who are not already infertile, and many people with a low AMH conceive without help. When is it urgent? A very low AMH with absent periods before 40 should prompt a POI work-up rather than reassurance.
Why AMH is high
A high AMH is discussed less often but is clinically useful:
- Polycystic ovary syndrome (PCOS) — much the commonest cause. Levels typically run two to three times higher than average because PCOS ovaries carry many small antral follicles, each contributing AMH. A high AMH supports the diagnosis but does not make it alone: PCOS is diagnosed from a combination of irregular cycles, signs of excess androgens and ultrasound findings, as Cleveland Clinic notes.
- A naturally large reserve, often simply reflecting younger age.
- Granulosa cell tumor of the ovary — a rare but important cause. These tumors secrete AMH, so an unexpectedly high level, especially after menopause or alongside a pelvic mass or abnormal bleeding, warrants imaging and gynecology review.
A high AMH also flags a strong response to IVF drugs and a higher risk of ovarian hyperstimulation, so fertility specialists use it to lower the stimulation dose. When is it urgent? A high AMH with a pelvic mass, or any measurable AMH long after menopause, needs prompt evaluation.
What to test alongside
AMH is only one part of an ovarian-reserve or hormonal work-up. Depending on the question, it is read with:
- FSH, LH and estradiol — the early-cycle hormones that, with AMH, frame ovarian reserve and menstrual problems.
- Testosterone, free testosterone and SHBG — for the excess-androgen side of a high-AMH, PCOS picture.
- DHEAS and 17-OH-progesterone — adrenal androgens and a check for non-classic congenital adrenal hyperplasia that can mimic PCOS.
- Prolactin and TSH — other common causes of irregular cycles to rule out.
- Glucose and HbA1c — for the insulin resistance that often accompanies PCOS.
- hCG — to exclude pregnancy before a fertility work-up.
An ultrasound antral follicle count is the imaging companion to AMH and is often done at the same visit.
What to do about an abnormal result
- Don’t act on a single number. AMH is interpreted alongside your age, an antral follicle count, FSH and your history — never in isolation.
- Confirm before you conclude. Assays differ, so an unexpected result is worth repeating, ideally at the same lab; and mention any hormonal contraception, which lowers AMH temporarily.
- For a low AMH: see a gynecologist or a reproductive endocrinologist (fertility specialist) to discuss your timeline — while remembering it does not mean you cannot conceive. If you are under 40 with missed periods, ask about a POI evaluation and about protecting bone and heart health.
- For a high AMH: with irregular periods or signs of excess androgens, your doctor will work through a PCOS assessment; an unexpectedly high level with a pelvic mass needs prompt gynecology imaging.
- Who to see first: your primary-care doctor or gynecologist, who can coordinate the right next test. If you are simply planning a pregnancy, a preconception check-up is more useful than an AMH bought as a stand-alone “fertility test,” which ACOG advises against for women who are not infertile.
Mini-FAQ
Does a normal AMH mean I can get pregnant?
No. ACOG and ASRM both say AMH does not predict natural fertility or how quickly you will conceive in women who are not infertile. It estimates the size of your remaining egg pool, not egg quality or your monthly chance of pregnancy — and age is a stronger predictor.
What counts as a low AMH level?
There is no single cut-off, and it depends on age. Broadly, below about 1.0 ng/mL (roughly 7 pmol/L) suggests diminished ovarian reserve and below 0.5 ng/mL is very low. Levels fall naturally with age and become undetectable at menopause.
Does a high AMH mean I have PCOS?
A high AMH — often two to three times average — is common in PCOS and supports the diagnosis, but it is not diagnostic on its own; doctors also weigh irregular periods, signs of high androgens and ultrasound. Rarely, a very high level points to an ovarian granulosa cell tumor.
Can I test AMH on any day of my cycle?
Yes. AMH stays relatively stable across the menstrual cycle, so unlike FSH and estradiol it does not need to be timed to your period. Hormonal contraception and GnRH-agonist treatment can lower it temporarily.
Does a low AMH mean I am infertile or in early menopause?
Not by itself. A low AMH means fewer eggs remain and may predict a weaker response to IVF, but many people with low AMH conceive naturally. A very low level with missed periods and a high FSH before age 40 raises concern for primary ovarian insufficiency and warrants specialist review.
