AMH (anti-Müllerian hormone) is a hormone produced by cells in the ovaries that serves as the best available marker of ovarian reserve, a term describing how many eggs remain. In women of reproductive age, AMH levels typically range from 1.0 to 3.0 ng/mL, declining steadily with age until they become nearly undetectable around menopause. The test has become a standard part of fertility evaluation, but AMH plays important biological roles well beyond the fertility clinic.
What AMH Does in the Body
AMH was originally discovered for its role in male fetal development. Starting around the 8th week of pregnancy, cells in the developing testes produce AMH at high concentrations (around 50 ng/mL) to break down structures called Müllerian ducts. These ducts would otherwise develop into the uterus, fallopian tubes, and upper vagina. In female fetuses, AMH production from the ovaries doesn’t begin until roughly the 23rd week of gestation, and at much lower levels.
In adult women, AMH acts as a brake on the ovaries. It’s produced by small, growing follicles (the fluid-filled sacs that contain eggs) and prevents dormant follicles from being activated too quickly. Think of it as a pacing mechanism: without AMH, the body would recruit its stored eggs faster and run out sooner. Studies in mice without AMH showed exactly this pattern. Their follicles matured earlier and in greater numbers, but the supply was exhausted significantly sooner than normal.
AMH also dials down the ovaries’ sensitivity to FSH, the pituitary hormone that drives follicle growth each cycle. This interaction helps determine how many follicles develop in a given month and is one reason AMH levels matter so much in fertility treatment planning.
AMH Levels by Age
AMH declines predictably over a woman’s reproductive years. These are approximate values on the lower side of the expected range for each age:
- Age 25: 3.0 ng/mL
- Age 30: 2.5 ng/mL
- Age 35: 1.5 ng/mL
- Age 40: 1.0 ng/mL
- Age 45: 0.5 ng/mL
Levels below 1.0 ng/mL are generally considered low, and levels around 0.4 ng/mL are considered severely low. That said, there’s real debate among experts about where to draw the line between “normal” and “low,” because AMH varies widely between individuals of the same age. A 32-year-old with an AMH of 1.2 ng/mL has a lower-than-average level for her age, but that alone doesn’t mean she’ll have difficulty conceiving.
What AMH Actually Tells You About Fertility
AMH reflects the number of small growing follicles in the ovaries at any given time, which in turn reflects the larger pool of dormant eggs. It’s the best blood test available for estimating egg quantity. But there’s a nuance worth understanding: in younger women, AMH correlates well with the number of growing follicles but doesn’t always track closely with the total remaining egg supply. In women of later reproductive age, the correlation tightens and AMH becomes a more direct reflection of how many primordial (stored) follicles are left.
What AMH cannot tell you is egg quality. A woman with a lower AMH may still have eggs that are perfectly capable of producing a healthy pregnancy, while a woman with high AMH might have other factors affecting her fertility. AMH is one piece of the picture, not the whole story.
AMH in IVF and Fertility Treatment
Where AMH becomes especially practical is in predicting how the ovaries will respond to the hormone medications used during IVF. Higher AMH levels consistently correlate with a greater number of eggs retrieved. This makes AMH valuable for setting expectations: a woman with a high AMH is more likely to produce many eggs in one cycle, while a woman with a low AMH may need adjusted medication doses or multiple cycles.
However, the connection between AMH and what happens after egg retrieval is weaker. AMH is less reliable for predicting embryo quality or pregnancy rates on its own. It’s useful for stratifying patients and counseling them about anticipated egg yield, but it becomes less predictive once you move past retrieval and into the question of whether a given embryo will implant and develop.
AMH and PCOS
Women with polycystic ovary syndrome (PCOS) typically have elevated AMH levels, often well above the normal range. This happens because PCOS is characterized by a large number of small follicles in the ovaries, and those follicles are what produce AMH. Research has shown that using an AMH cutoff of 3.8 ng/mL, combined with signs of excess androgens (like acne or excess hair growth) or irregular periods, can identify PCOS with up to 100% specificity. AMH isn’t yet part of the formal diagnostic criteria for PCOS in all guidelines, but many clinicians use it as a supporting tool, particularly when ultrasound results are unclear.
What Can Affect Your AMH Results
One of AMH’s advantages over other fertility hormones like FSH is that it remains relatively stable throughout the menstrual cycle, so the test can be drawn on any day. But “relatively stable” isn’t the same as immune to outside influence.
Hormonal contraceptives suppress AMH levels meaningfully. A study of over 27,000 women found that combined oral contraceptive pills, vaginal rings, and hormonal implants each lowered AMH by roughly 22 to 24%. Progestin-only pills reduced levels by about 15%, and hormonal IUDs had a smaller but still measurable effect of about 7%. If you’re on hormonal birth control and get an AMH test, your result will likely read lower than your true baseline. Some providers recommend stopping contraception for a period before testing, though practices vary.
Vitamin D status also appears to influence AMH. Research found that AMH levels in premenopausal women were about 18% lower in winter than in summer, a seasonal dip that was prevented by taking 1,000 IU of vitamin D daily during winter months. This doesn’t mean vitamin D supplements will raise your ovarian reserve. It suggests that vitamin D deficiency may cause AMH readings to underestimate the actual number of growing follicles.
AMH and Menopause Timing
Because AMH declines steadily as the egg supply shrinks, researchers have explored whether it can predict when menopause will arrive. The concept is straightforward: if AMH reflects remaining follicles, very low levels should signal that menopause is near. Studies have found that women whose AMH drops below approximately 0.012 ng/mL reach their final menstrual period within a median of about 19 months, while women with AMH still above that threshold typically have a median of about 5 years before menopause. Age remains the strongest predictor of menopause timing, but AMH adds useful information, particularly for women wondering if their symptoms might signal an earlier-than-expected transition.