Theory 17/Reproductive Biology /Ovarian physiology/3 min
AMH Is a Proxy, Not a Measure
A hormone that correlates with egg number is being read as a countdown timer.
Anti-Mullerian hormone is a proxy for follicle number rather than a measure of ovarian reserve, so it should predict response to stimulation better than it predicts the time to menopause, and using it as a reserve clock misleads patients.
01The evidence
- Anti-Mullerian hormone concentration has been reported to have limited prognostic value for the density of primordial and primary follicles, which questions its use as an accurate parameter of ovarian reserve.Human Reproduction
02The tension
AMH is used clinically as a reserve measure and as a predictor of menopause timing. It performs well for one purpose, predicting response to ovarian stimulation, and poorly for the other, which is a pattern that should have limited its second use but did not.
03The theory
AMH is produced by small growing follicles. Its concentration therefore reflects the number of follicles currently in the growing pool, which is a flow rather than a stock.
If the hormone measures flow, it predicts how a patient will respond to stimulation, because that depends on the recruitable pool. It does not measure the stock of primordial follicles, which is what determines the time to menopause.
The prediction is that AMH should correlate with stimulation response but weakly with the age at menopause after controlling for age, and that the two uses should be separated in clinical guidance.
The consequence is a communication problem more than a scientific one: patients are being told a number that answers a different question from the one they are asking.
04What this is not
The reserve reading treats the hormone as a gauge of remaining follicles. This treats it as a flow measurement, which predicts good performance for stimulation and poor performance for menopause timing.
05Predictions
- P1AMH should predict stimulation response better than age at menopause.
- P2The correlation with menopause timing should weaken after controlling for age.
- P3Direct follicle counts should diverge from AMH at the extremes.
06What would refute it
AMH predicting menopause timing as well as it predicts stimulation response would restore the reserve reading.
07What it would change
It would separate two clinical uses and change how patients are counselled.
08Evidence base
- Serum AMH concentration has limited prognostic value for follicle density — Human Reproductionhttps://ouci.dntb.gov.ua/en/works/ldLvBmBl/