Fertility is Not a Numbers Game

Why the AMH ‘egg timer test’ sells panic to some women and false comfort to others

In this issue:

• Why AMH cannot tell you how many eggs you have left or how much time you have

• Where AMH is clinically useful and where it provides very little value

• What actually determines whether an egg makes it to ovulation

• The core physiological markers that shape egg quality and pregnancy outcomes

• A simple framework for when testing is worth doing and when it adds very little

A 25‑year‑old sat down in my clinic recently and announced, matter‑of‑fact, “I only have 11 eggs left.” As if someone with a magical microscope had zoomed in and done a stocktake.

We don’t have a test that can do that. A number, whether it comes from an AMH blood test or an ultrasound follicle count (ie. how many follicles have been recruited that month), can’t tell us exactly how many eggs you have left, or how many months you’ve got before you “run out of time.”

This issue is my attempt to pull that apart: why your fertility is not a numbers game, why AMH is the noisiest, least helpful number being sold to women as an “egg‑timer test”, and where the real, powerful levers on your future baby actually live.

The Rise of the Egg‑Timer Test

We haven’t just started having children later; that shift has been underway for decades. What’s changed recently is that women are finally being told, loudly and repeatedly, that fertility declines with age.

At the very same time, a whole industry has grown up around “doing something about it.”

The reality: more people in their 30s are still studying, building careers, saving for a home deposit, and looking for the right partner. The years when biology is more relaxed about conception are now the same years a lot of people are still just trying to get their lives off the ground.

The market response: whether you’re actively trying or just thinking about babies one day, your feed now offers you:

• “Fertility tests” with AMH as a paid add‑on to “check your egg reserve”

• Egg‑freezing payment plans

• “Know your number, own your timeline” campaigns

• At‑home kits and lab bundles marketed as “check your fertility”

Some of this is genuinely good news. Onco‑fertility exists now: people about to have chemo can freeze eggs or embryos. We pick up premature ovarian insufficiency (POI) earlier than we used to.

If you’re already heading for IVF or planning egg freezing, AMH can be genuinely useful as a way to gauge how your ovaries are likely to respond to the drugs.

The problem is that the same test has been pushed out to a much bigger group of women: the late‑night‑Googling, “I’m 34, am I running out of eggs?” crowd, as if it were the obvious solution.

Depending on the number you’re handed, that can mean years of background anxiety about being “low”. Or it can give you a false sense of security, that a “good” AMH implies abundant fertility so that you don’t to need to think about for ages.

Woven through all of this is a very particular story: that a single number can tell you how fertile you are and how fast you should move.

Front and centre in that story is AMH.

Rebadged as the “egg‑timer test”, it’s sold as if it can count your remaining eggs and ping you when the sand is about to run out.

What AMH actually is

Your ovaries are full of tiny resting follicles - a troupe of young ballet dancers. Each month a small group is invited to start training, and one will usually be picked as the prima ballerina.

Those in‑training follicles make AMH, so more in play means higher AMH; fewer means lower AMH. AMH is like crowd control for these small follicles: it paces which ones step on stage. What it does not do is act as a timer that rings an alarm to warn you you’re running out of eggs.

What the evidence says about AMH and fertility

There’s no neat, straight‑line relationship between your AMH result and your personal chance of conceiving naturally. Lower AMH does not mean a proportionately lower chance of conceiving – unless it is very low, or very high in a PCOS‑type picture, and even then, that’s a minority of cases.

“Very low / very high” bands that are generally considered significant:

• “Very low”: under about 5–8 pmol/L (Australia/UK) or roughly 0.7–1.1 ng/mL (USA)

• “Very high” in a PCOS‑type pattern: over about 25–30 pmol/L (Australia/UK) or roughly 3–4 ng/mL (USA)

In between those bands, there’s no clear linear relationship between AMH and who will and won’t get pregnant naturally.

This is the part the marketing rarely explains.

IVF and egg freezing – when AMH is useful

If you’re doing IVF or egg freezing, AMH is genuinely useful because it helps estimate how strongly your ovaries are likely to respond to stimulation. Higher AMH usually means we can expect more follicles to respond to the drugs; lower AMH usually means fewer.

That helps with dosing (how much medication to start with, how cautious we need to be about OHSS – ovarian hyperstimulation syndrome) and with expectations (roughly how many eggs we’re aiming for, and whether one cycle is likely to be enough or if you may need more than one).

When AMH does matter: the extremes

Very low AMH: when it’s a red flag

When AMH is very low for your age and there are other signals: irregular or absent periods, rising FSH, strong family history of early menopause, or past chemo/major ovarian surgery, it becomes a clue.

In that context, very low AMH can help diagnose premature ovarian insufficiency (POI) or significant diminished ovarian reserve after surgery or treatment.

It still doesn’t mean “no chance”: people with POI can and do have spontaneous ovulations and pregnancies. It does mean your window is likely shorter, and you deserve a proper work‑up and plan, not a pat on the head.

Very high AMH: PCOS and over‑response

At the other end, very high AMH usually means lots of small follicles, often in a polycystic ovary pattern. High AMH in that context does not mean “super fertility.” It usually means more stalled or irregular cycles, a higher risk of over‑responding to fertility drugs, and more risk of ovarian hyperstimulation syndrome (OHSS) if IVF isn’t carefully managed.

Here, AMH becomes a safety tool: it helps your clinician guide protocols and avoid flooding an already sensitive ovary.

So at the extremes, AMH is useful; everywhere in the middle, it’s context only, not a crystal ball.

What really matters: are you ovulating?

Another client recently suggested a repeat AMH to “see how things were tracking” after a result in the lower (but not ‘very low’) zone. Her doctor quite rightly said, “It probably won’t change what we do; we’re interested in whether you’re ovulating.”

I agreed, and added that whether your ovaries are home to hundreds of thousands of eggs or somewhat fewer, each month still comes down to the same question: Did you ovulate?

For most women who are not at the very extremes of AMH, there are still plenty of eggs waiting in the background; you don’t need all of them, you just need one to make it to ovulation.

Real empowerment: your labs, not your egg timer

AMH and egg freezing are sold as empowerment: “Know your number.” “Take control.” “Buy yourself time.” But real empowerment does not come from knowing a single number.

When I review labs for someone who wants to support her fertility, whether she is planning to conceive now or in a few years, I do not fixate on her AMH to the first decimal place. I focus on the more fundamental markers that reflect underlying physiology, including:

• Glucose, insulin and lipids – how well her body handles energy.

• Thyroid function – because thyroid hormones set the pace for ovulation, implantation and early pregnancy.

• Iron, B12 and folate – can she actually oxygenate and build tissue.

• Liver function and inflammatory markers – how well she clears hormones and handles chronic low‑grade inflammation.

• Properly timed sex hormones across a cycle – not just “Day 3 plus a random luteal progesterone,” but the actual pattern of how her body is doing ovulation.

On top of that, I care deeply about things you can’t see in a single blood draw: nervous system regulation, sleep, nutrition, movement, endocrine disruptor exposure, genetics, microbiome, and how she makes and uses energy.

This paints a much richer picture of reproductive health. And if you decide that you’d like to try for a baby soon, or pursue egg freezing or IVF, it’s this more comprehensive set of labs plus your health history that will tell us where to focus on improving egg quality.

On my panel, AMH is often the background context number in the room. If it’s very high or very low, I pay attention. Otherwise, I mostly ignore it.

When AMH Deserves a Seat at The Table

• If your cycles are regular, you feel generally well, and you’re not trying yet (or only just starting), you probably don’t need an AMH test. It won’t change the advice: watch your cycles, mind your timing, look after the basics.

• If you’ve had chemo, pelvic radiation, major ovarian surgery, or there’s a strong family history of very early menopause, AMH can be useful, but only as part of a bigger conversation that includes FSH, estradiol, and what your periods are actually doing.

• If you’re about to spend serious money and energy on egg freezing or IVF, then yes: get an AMH.

• In that context it earns its keep as one piece of the planning puzzle for dosing, response, and safety, not as your personal fertility score.

For the fridge, the mirror, or your better judgement

• AMH reflects follicle activity, not a countdown to infertility

• Extremes of AMH carry clinical meaning; the middle range rarely changes management

• Ovulation remains the central monthly event that influences conception

• Metabolic, hormonal and inflammatory markers shape fertility and egg quality far more than a single hormone value

• Testing should be guided by context, not anxiety

Warmly, Sonja

New Here? Head to the About & Welcome pages for why I started Baby Ready Health and a bit about me.

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This post is for educational purposes only and is not medical advice. Always consult a qualified practitioner before making decisions about your health.

References:

Steiner, A. Z., Herring, A. H., Kesner, J. S., Meadows, J. W., Stanczyk, F. Z., Hoberman, S., & Baird, D. D. (2011). Antimüllerian hormone as a predictor of natural fecundability in women aged 30-42 years. Obstetrics and gynecology, 117(4), 798–804. https://doi.org/10.1097/AOG.0b013e3182116bc8

Copp T, Thompson R, Doust J, et al. Community awareness and use of anti-Müllerian hormone testing in Australia: a population survey of women. Hum Reprod. 2023;38(8):1571-1577. doi:10.1093/humrep/dead111

Lin C, Jing M, Zhu W, et al. The Value of Anti-Müllerian Hormone in the Prediction of Spontaneous Pregnancy: A Systematic Review and Meta-Analysis. Front Endocrinol (Lausanne). 2021;12:695157. Published 2021 Oct 13. doi:10.3389/fendo.2021.695157

Steiner, A. Z., Herring, A. H., Kesner, J. S., Meadows, J. W., Stanczyk, F. Z., Hoberman, S., & Baird, D. D. (2011). Antimüllerian hormone as a predictor of natural fecundability in women aged 30-42 years. Obstetrics and gynecology, 117(4), 798–804. https://doi.org/10.1097/AOG.0b013e3182116bc8