AMH: what anti-Müllerian hormone says about your egg reserve

AMH (anti-Müllerian hormone) is made by the small follicles in your ovaries, the little sacs where your eggs mature. The more of those follicles you have, the higher your AMH. That makes it the best blood value we have for estimating your egg reserve.

But it comes with an honest disclaimer, and you're getting it in the first paragraph rather than buried at the bottom: AMH doesn't predict your chance of conceiving naturally. That's not an opinion, it has been measured (PMID 29049585).

In this piece I'll lay out what AMH does tell you, what it doesn't, and in which situations an AMH test genuinely earns its place.

What is AMH exactly?

AMH stands for anti-Müllerian hormone. It's produced by the small, still-resting follicles in your ovaries. The amount of AMH in your blood therefore roughly tracks the number of follicles you have left: fewer follicles, less AMH.

Every woman is born with her complete supply of egg cells, roughly one to two million. That supply never grows back and shrinks a little every month.

AMH is a stock gauge. Not of the quality of your eggs, only of the quantity still in play.

What does AMH say about your fertility?

Less than many test providers would have you believe. A large American study followed 750 women aged 30 to 44 who were trying to conceive: women with low AMH got pregnant just as often as women with normal values (JAMA 2017, PMID 29049585). For your chance of a spontaneous pregnancy right now, AMH is no crystal ball.

That may sound like the test is pointless. It isn't that black and white.

AMH does say something about the size of your reserve, and so about how much room is left looking ahead. In an IVF programme, for example, doctors use your AMH to estimate how many eggs a retrieval might yield and how to dose the medication.

The difference sits between "can I get pregnant now" and "how much reserve do I have left". AMH doesn't answer the first question. It answers the second reasonably well.

What is a good AMH level?

For adult women, the broad population range our doctors work with in their reviews runs from about 1 to 13 micrograms per litre. What counts as "good" mostly depends on your age: a value of 1.2 is normal around 40 and strikingly low at 25. A bare number without your age next to it says very little.

International reference studies show the median glides down from roughly 3 to 4 micrograms per litre around age 25 to under 1 around 45 (PMID 22579227).

Take two women with exactly the same result of 1.2 micrograms per litre. For Karin, 41, that's a tidy value that fits her age neatly. For Femke, 26, that same number is low, and a good reason not to keep postponing her plans indefinitely. Same number, different message.

You'll find the full table of averages per age group, caveats included, in our article on AMH levels by age. Want a first read on your own result? Enter it into our AMH level check.

How fast does your AMH decline?

Your egg reserve declines throughout life, and your AMH declines with it. Researchers at the University of Edinburgh calculated that at 30 a woman has about 12 percent of her original reserve left, and at 40 around 3 percent (PMID 20111701).

Don't let those percentages frighten you. They sound dramatic, but 3 percent of over a million is still tens of thousands of follicles, and a pregnancy needs exactly one egg a month.

What the percentages do show: the decline isn't a straight line. It speeds up after 35, which is exactly why age is the essential context for any AMH result.

AMH and PCOS

With PCOS the story runs in reverse: the ovaries hold unusually many small follicles, so AMH often comes out two to three times higher than average. A high AMH isn't automatically good news about your reserve; it can also belong to this picture.

Interestingly, that insight is now official policy. The 2023 international PCOS guideline allows an AMH measurement in adults to replace the ovarian ultrasound as one of the diagnostic criteria (PMID 37580037).

If you recognise symptoms such as an irregular cycle, acne or excess hair growth alongside a high AMH, read on in our article on PCOS testing and discuss the full picture with your GP.

AMH and menopause

Approaching menopause, AMH sinks to unmeasurably low values, often years before your final period announces itself. A very low value alongside persistently irregular cycles can fit the run-up to menopause, especially past 45.

Even so, doctors don't use AMH to put menopause on the calendar. The spread between women is too wide for that: two women with the same low value can be years apart.

Here too: the value is context, not a verdict.

When is an AMH test worthwhile, and when not?

An AMH test is most useful when the outcome can change a concrete decision. Think of weighing up egg freezing, preparing for IVF, or adding context to PCOS symptoms. If you only want to know whether you can get pregnant right now, this is the wrong instrument.

This table is deliberately strict. We sell this test, and that's exactly why I think you should know which row you're in before you buy it.

AMH, FSH or an ultrasound: what measures what?

There are three ways to picture your egg reserve: the AMH value in your blood, the FSH value in your blood, and counting antral follicles on an ultrasound. They look at the same reservoir, but each from a different angle and with its own instructions for use.

AMH comes straight from the small follicles themselves and can be drawn on any cycle day. That makes it the most practical of the three, and usually the most sensitive early gauge.

FSH works indirectly: your brain sends more FSH when the ovaries respond less, so a high FSH fits a smaller reserve. But the value is only usable on cycle day 2 to 5, and it fluctuates from cycle to cycle on top of that.

The ultrasound counts the visible antral follicles (the AFC) and gives the most direct picture, but requires an appointment and a trained counter. In practice, AMH and AFC usually move neatly in step (PMID 22579227); clinics often use them side by side.

AMH and egg freezing

When weighing up egg freezing, AMH plays an honestly useful role. The value helps the clinic estimate how many eggs one retrieval might yield, and so how many rounds are needed to build a workable stock. Clinics often aim for 15 to 20 frozen eggs.

For anyone torn between now and five years from now, the measurement isn't scaremongering but planning information. A value that fits your age buys calm; a value that lags makes the conversation more concrete and earlier.

How many eggs remain per age, and why quality outweighs quantity, is covered in our article on egg cells and age.

Can you raise your AMH?

No, not really. Your egg reserve is fixed from birth, and no supplement or diet adds new follicles. So be sceptical of anything promising to "boost" your AMH: a slightly higher reading doesn't mean a bigger reserve.

What can happen: your value is temporarily pushed down by hormonal contraception. During pill use, researchers consistently measure lower AMH, and the only honest fix is stopping and re-testing after two to three months (PMID 32362164).

Smoking is also linked to lower values and an earlier menopause. Quitting won't enlarge your reserve, but it protects what's there.

Frequently asked questions

What is a good AMH level for my age?

It differs per age group: around 25 the median is roughly 3 to 4 micrograms per litre, around 40 about 1. Our table by age lays out the averages and the spread.

What does a low AMH mean?

A smaller egg reserve than average for your age. It doesn't mean you can't get pregnant: in research, women with low AMH conceived spontaneously just as often (PMID 29049585). Always discuss a low result with your GP, certainly if you're hoping to conceive.

Can I test AMH while on the pill?

You can, but the result will read artificially low and is hard to interpret. For an honest picture, stop first in consultation with your GP and measure after two to three months (PMID 32362164).

Which cycle day should I test AMH on?

AMH barely fluctuates across your cycle, so any day works. That makes it more practical than FSH, which is tied to specific cycle days. How the blood draw works is covered in AMH testing.

How does AMH relate to follicles on an ultrasound?

They measure the same reservoir in two ways: the ultrasound counts the visible antral follicles, the blood measures the hormone those same follicles produce. The two results usually move together.

Does AMH drop with stress or exercise?

No, there's no good evidence for that. AMH reflects the number of small follicles, and that number doesn't change with a busy week or a marathon. The known disruptors are hormonal contraception, smoking and the natural effect of age itself.

How often is it worth re-measuring AMH?

A single measurement is a snapshot; it's the trend over years that makes the value informative. If a concrete decision comes back on the table, a new measurement is logical. So always keep your earlier result, including the unit and the date.

My honest summary after all of the above: AMH is a useful stock gauge and a useless fortune teller. Have your value measured when a real decision is on the table, such as egg freezing, IVF preparation or PCOS work-up, and take the result to your GP rather than to Google at 3am. If you want to look wider than reserve alone, the fertility assessment with several hormone values is the more logical starting point. More background on the measurement itself is on our biomarker page for AMH.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP or your gynaecologist.

References

• Steiner AZ, Pritchard D, Stanczyk FZ, et al. Association Between Biomarkers of Ovarian Reserve and Infertility Among Older Women of Reproductive Age. JAMA, 2017. PMID 29049585.
• Wallace WH, Kelsey TW. Human ovarian reserve from conception to the menopause. PLoS One, 2010. PMID 20111701.
• La Marca A, Spada E, Grisendi V, et al. Normal serum anti-Müllerian hormone levels in the general female population and the relationship with reproductive history. Eur J Obstet Gynecol Reprod Biol, 2012. PMID 22579227.
• Teede HJ, Tay CT, Laven JJE, et al. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. Hum Reprod, 2023. PMID 37580037.
• Landersoe SK, Forman JL, Birch Petersen K, et al. Ovarian reserve markers and endocrine profile during oral contraception. Gynecol Endocrinol, 2020. PMID 32362164.
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