The AMH 'egg-timer' test doesn't predict your chance of getting pregnant

The at-home "egg-timer" test — a finger-prick that measures anti-Müllerian hormone, or AMH, and promises to reveal your fertility or how much time you have left to conceive — cannot deliver on that promise for the women most likely to buy it. In the best study of the question, women with "low" ovarian-reserve hormones were no less likely to get pregnant than women with normal levels, and the leading obstetrics body says the test should not be used to counsel women who are not already known to be infertile [s1][s2].

What AMH actually is

AMH is made by small follicles in the ovary, and its level roughly tracks the size of the remaining egg pool. That makes it genuinely useful in one setting: fertility clinics use it to anticipate how a woman will respond to the ovarian stimulation of IVF, and to tailor drug doses [s2]. The marketing leap — from "reflects the number of eggs" to "predicts whether and when you'll conceive naturally" — is where the evidence collapses. Egg quantity and the monthly chance of conception are not the same thing.

The distinction that gets lost is between egg quantity and egg quality. AMH is, at best, a rough gauge of how many eggs remain; it says nothing about whether those eggs are chromosomally normal, which is what actually falls with age and drives the decline in natural fertility and the rise in miscarriage. A woman can have a large egg pool and mostly abnormal eggs, or a small pool and enough good ones. That is why AMH earns its place in an IVF clinic — where the question is literally how many eggs a stimulation cycle will yield, and the dosing turns on it — and loses it as a consumer fertility forecast, where the question is whether a particular woman will conceive [s2].

The study that tested the promise

Researchers followed 750 women aged 30 to 44 with no history of infertility who had been trying to conceive for three months or less, measuring their ovarian-reserve hormones and tracking who became pregnant [s1]. If AMH predicted natural fertility, women with low levels should have conceived less often. They did not.

Women with low AMH (under 0.7 ng/mL) had a 65% predicted chance of conceiving within 6 cycles, against 62% for women with normal levels — no meaningful difference [s1]. By 12 cycles the figures were 84% for the low-AMH group and 75% for the normal group, again not significantly different [s1]. The same held for high follicle-stimulating hormone, the other marker these tests often report: 63% versus 62% within 6 cycles [s1]. The authors' conclusion was unambiguous — biomarkers indicating "diminished ovarian reserve" were not associated with reduced fertility, and the findings "do not support the use" of these hormone tests to assess natural fertility in such women [s1].

What the guidance says

Professional guidance followed the evidence. The American College of Obstetricians and Gynecologists advises that using serum AMH for fertility counselling in women without a diagnosis of infertility "is not currently supported by data from high-quality sources," and cautions specifically against reading much into AMH in any population with a low prevalence of infertility — including women who have never tried to conceive [s2]. That is precisely the direct-to-consumer market: people buying reassurance or a planning signal, not patients being worked up for infertility.

The menopause-test version has the same flaw

The same hormones are repackaged in at-home "menopause" or "perimenopause" tests, which usually measure follicle-stimulating hormone and claim to tell a woman where she is in the transition. The problem is biological: FSH swings widely from day to day and cycle to cycle in the perimenopause, so a single value is a snapshot of a moving target and cannot reliably time menopause or confirm the transition. The study above found high FSH no more predictive of conception than AMH [s1]. As elsewhere in this category, the test measures something real but answers a different question than the one on the box — the same gap that runs through DNA-based diet tests and fertility-tracking apps sold as contraception.

What this means for a reader

A low at-home AMH result is not evidence that a woman will struggle to conceive, and a normal result is not a guarantee she won't — for natural fertility, the number simply does not carry that information [s1][s2]. The strongest predictor of the chance of conceiving remains age, not a hormone panel; the ways age genuinely shapes fertility and the real, measurable success rates of egg freezing are far more informative than an egg-timer readout. For a woman with an actual infertility diagnosis, AMH has a legitimate clinical role in her care [s2]. Sold to everyone else as a personal fertility forecast, it is a test in search of a question it can answer.

Sources

• [s1] JAMA — Association Between Biomarkers of Ovarian Reserve and Infertility Among Older Women of Reproductive Age (2017-10-10)
• [s2] Obstetrics & Gynecology — ACOG Committee Opinion No. 773: The Use of Antimüllerian Hormone in Women Not Seeking Fertility Care (2019-04-01)