What an AMH test actually tells you

Anti-Müllerian hormone is produced by small growing follicles in the ovary, and the amount circulating correlates with how many of those follicles there are. That is a real and useful measurement. It is also one of the most over-interpreted tests in medicine.

What it is good for

AMH does two things well.

It predicts response to ovarian stimulation. This is what it was validated for. A fertility clinic uses AMH, alongside antral follicle count on ultrasound, to choose a drug protocol and to estimate how many eggs a stimulation cycle will yield. It is genuinely good at this.

It supports a PCOS diagnosis. AMH is typically high in PCOS because there are many small follicles, and current criteria allow a raised AMH as an alternative to ultrasound findings — see PCOS beyond the ovaries.

It also has a role in assessing suspected primary ovarian insufficiency, and in estimating the impact of cancer treatment on ovarian function.

What it does not do

It does not predict your chance of conceiving naturally. This is the important one. Studies following women without known infertility have consistently found that AMH is a poor predictor of time to pregnancy. Women with low AMH for their age conceive at broadly similar rates to those with normal AMH.

The reason is a category error. AMH is a measure of quantity, not quality. What determines whether a given cycle produces a viable pregnancy is mainly whether the egg released is chromosomally normal — and that is driven by age, not by how many follicles remain. A 32-year-old with low AMH is releasing 32-year-old eggs.

It does not tell you when you will reach menopause, other than very loosely at a population level.

It does not tell you whether you should have a baby now. It cannot, because it does not measure the thing that matters.

Why the direct-to-consumer version is a problem

AMH is widely marketed as a "fertility test" or an "ovarian reserve check", often bundled into wellness panels. The result arrives as a number with a reference range and, frequently, an implied verdict.

Two failure modes follow. A low result causes considerable distress and sometimes prompts expensive decisions — egg freezing, rushing into treatment — on the basis of a number that does not predict natural conception. A high or normal result offers false reassurance, because it says nothing about egg quality, tubal patency, sperm, or anything else that actually causes infertility.

Professional bodies have been explicit: AMH is not recommended as a screening test for fertility in women without a fertility problem.

Things that move the number

Worth knowing before treating any single result as fixed:

• Hormonal contraception lowers AMH, sometimes substantially. A result taken on the pill can under-represent reserve, and it may take months after stopping to normalise.
• Assay variation. Different laboratories and platforms produce different values. Comparing a result from one lab to a reference range from another is not reliable.
• Vitamin D status, BMI and smoking have been associated with modest differences.
• Age, which is the dominant factor and the one that makes any result meaningless without it. AMH must be interpreted against age, not against a single range.

What to do instead

If you are trying to conceive and it is not happening, the useful investigations are not AMH in isolation. They are: confirming you ovulate, checking tubal patency, and a semen analysis for your partner — male factor contributes to roughly half of cases and is the cheapest thing to check. How long conception actually takes covers when to start.

If you are considering egg freezing, AMH is genuinely relevant, because it predicts how many eggs a cycle will yield and therefore how many cycles you might need. Egg freezing, without the marketing covers the rest of that decision.

If you have irregular cycles, AMH is one useful piece of a PCOS or POI workup — but only as part of one.

If you simply want to know something about your reproductive health, the more informative thing is whether you ovulate regularly, and what your cycles are actually doing. That is free, it is observable, and it changes over time in ways a single blood test does not capture. How to tell when you ovulate covers the signals.

The record beats the number

A single AMH value is a snapshot of one thing. Twelve months of cycle data tells you whether you ovulate, how consistently, whether your luteal phase is adequate, and how your cycles are trending with age — which is considerably more information about your reproductive function than a hormone level interpreted against a population range.

Naked is built to hold that: cycles, ovulation signals, symptoms and everything alongside them, tracked over the years where the trend is the actual signal. If you do end up in a fertility clinic, that record is more useful to them than any single test you could have bought.