AMH, or anti-Müllerian hormone, is a protein produced by cells in your ovaries that reflects how many eggs you have left. It’s the most reliable blood marker of what doctors call “ovarian reserve,” and it’s widely used in fertility assessments, IVF planning, and predicting when menopause might arrive. A simple blood test measures it, and unlike most hormone tests, it can be drawn on any day of your cycle.
What AMH Actually Does in Your Body
AMH is produced by granulosa cells, the support cells that surround eggs as they develop inside tiny fluid-filled sacs called follicles. Specifically, the small growing follicles in your ovaries are the ones releasing AMH into your bloodstream. The more of these follicles you have, the higher your AMH level.
The hormone plays an active role in regulating how your eggs mature. It acts as a brake on two processes: it slows the rate at which dormant eggs “wake up” and begin developing, and it dampens the effect of FSH (the hormone your brain sends to recruit eggs each month). In other words, AMH helps pace how quickly your ovary uses up its egg supply. Without it, too many eggs would start developing at once, depleting the reserve faster.
The name comes from its original discovery in male fetal development, where it causes certain embryonic structures (Müllerian ducts) to regress. In females, that role isn’t relevant after birth, but the hormone takes on this entirely separate function in the ovaries.
What Your AMH Level Tells You
AMH is a measure of egg quantity, not egg quality. A lower level means fewer remaining eggs and a potentially shorter window for conception. A higher level means a larger pool of developing follicles. AMH correlates more tightly with the number of small follicles visible on ultrasound than age, FSH, or any other conventional hormone measurement does.
That said, AMH does not predict whether you will or won’t get pregnant. A woman with low AMH can still conceive naturally if the eggs she has are healthy, and a woman with high AMH may face other barriers to fertility. Think of it as one piece of the puzzle: it tells you about supply, not about the viability of any individual egg.
Typical AMH Levels by Age
AMH declines steadily with age as the follicle pool shrinks. A large study of women with regular cycles found the following median values:
- Ages 20 to 31: 4.20 ng/mL
- Ages 32 to 34: 3.70 ng/mL
- Ages 35 to 37: 2.60 ng/mL
- Ages 38 to 40: 1.50 ng/mL
- Ages 41 to 43: 1.30 ng/mL
- Over 43: 0.60 ng/mL
These are medians, meaning half of women at each age fall above and half below. There’s wide individual variation. For context, the bottom 5th percentile for women aged 20 to 31 is 1.19 ng/mL, while for women aged 38 to 40 it drops to 0.27 ng/mL. If your result falls below the 5th percentile for your age, that’s generally considered low ovarian reserve.
AMH is measured in ng/mL in the United States and most of the Americas, while many European and Australian labs report in pmol/L. The conversion is straightforward: multiply ng/mL by 7.18 to get pmol/L. So a result of 2.0 ng/mL equals roughly 14.4 pmol/L.
When AMH Is Tested
One of the practical advantages of AMH is that it stays relatively stable throughout your menstrual cycle. Levels are slightly higher during the first half of the cycle (follicular phase) than the second half (luteal phase), but the difference isn’t large enough to change the clinical interpretation. You don’t need to schedule the blood draw for a specific cycle day, which makes it more convenient than older hormone tests like FSH that require day-3 timing.
Factors That Can Skew Your Results
Several things can temporarily lower your AMH reading without reflecting a true change in your egg supply. The biggest one is hormonal birth control. Women currently using oral contraceptives have AMH levels roughly 41.5% lower than women who have never used them. This suppression reverses after stopping the pill, but it means getting tested while on birth control can give a falsely low result.
Smoking also lowers AMH. Current smokers show levels about 20% lower than nonsmokers, and even former smokers have levels around 13% lower. Interestingly, women who quit smoking appear to experience a temporary plateau in their AMH decline, suggesting some partial recovery. High coffee and tea consumption is associated with modestly higher AMH (about 10%), though the reason isn’t entirely clear. BMI, alcohol intake, and exercise levels don’t appear to have a meaningful effect.
High AMH and PCOS
While most people worry about low AMH, an unusually high level can signal polycystic ovary syndrome (PCOS). Women with PCOS have an excess of small antral follicles in their ovaries, and since those follicles produce AMH, levels can be significantly elevated. AMH may actually be more sensitive than ultrasound for detecting this excess, because it picks up on follicles too small to see on imaging (under 2 mm).
The relationship between high AMH and PCOS is linked to androgens. Women with PCOS who have elevated male hormones (hyperandrogenism) tend to have even higher AMH than PCOS patients without excess androgens. AMH levels also tend to be higher in women with insulin-resistant forms of the syndrome, suggesting the hormone may reflect disease severity. Research has found that combining an AMH cutoff of 3.8 ng/mL with the presence of either irregular periods or excess androgens achieves 83% sensitivity and 100% specificity for diagnosing PCOS.
AMH in IVF Planning
Fertility clinics use AMH to estimate how your ovaries will respond to stimulation medications before an IVF cycle. Women with higher AMH generally produce more eggs during a retrieval, and higher levels have been linked to better embryo quality. Clinics factor AMH alongside age, weight, and antral follicle count when choosing medication doses.
When AMH is very high (above 4 to 5 ng/mL), there’s an increased risk of ovarian hyperstimulation syndrome, a potentially serious overreaction to fertility drugs. For these patients, particularly those with PCOS, clinics typically use lower medication doses and closer monitoring. That said, AMH alone isn’t a perfect predictor of stimulation response. Ovarian sensitivity to medication doesn’t always scale neatly with AMH levels, so clinicians interpret the number alongside other factors rather than relying on it in isolation.
AMH as a Menopause Predictor
Because AMH tracks the shrinking follicle pool, it’s the strongest single predictor of when menopause will occur. In a study of women in their late reproductive years, AMH outperformed both FSH and inhibin B for predicting time to menopause. When FSH and inhibin B were included alongside AMH in the analysis, they added no additional predictive value.
The numbers paint a clear picture. Women whose AMH fell in the lowest quartile (below 0.20 ng/mL) reached menopause in a median of about 6 years. Those in the highest quartile (above 1.50 ng/mL) had a median of nearly 13 years remaining. Age matters too: a woman aged 35 to 39 with very low AMH still had a longer estimated time to menopause (about 10 years) than a woman aged 45 to 48 with the same AMH level (about 6 years), because age captures biological factors that AMH alone doesn’t. Each standard-deviation increase in AMH reduced the risk of reaching menopause by 44%, making it far more powerful than any other single biomarker for this purpose.