A hormone released by small ovarian follicles, used as a clue to ovarian reserve.
What AMH is and where it comes from
Anti-Müllerian hormone (AMH) is made by the small growing follicles in the ovaries. Because the number of these small follicles is closely tied to the level produced, AMH is used as one clue about ovarian reserve, meaning a rough estimate of how many follicles remain. Levels usually decline slowly with age, as the number of follicles falls over time. It is not a measure of egg quality and not a guarantee of fertility, only one small piece of a larger picture. For background on the condition itself, see the what is PCOS page.
Why it tends to be higher in PCOS
In PCOS the ovaries often hold many small, immature follicles. Since each of these follicles contributes a little AMH, the total tends to be higher than usual. This is why AMH is sometimes looked at during a PCOS assessment. Even so, a high level alone does not confirm PCOS, because some women without PCOS also have high values. A doctor always weighs it alongside symptoms, cycle pattern, and other hormone tests, as described on the hormones page.
How the test is taken and read
AMH is measured with an ordinary blood test and does not depend on a particular day of the cycle, so it is fairly easy to take. However, reference ranges differ between laboratories and test kits, so two readings from different places cannot always be compared directly. In a fertility context, it gives a rough idea of follicle number but does not accurately predict whether or when someone will conceive. Read more on the PCOS and fertility page.
When to talk to a doctor
If you receive an AMH result and are unsure what it means, bring the report to your appointment so it can be discussed in the right context. A low AMH at a young age may prompt a doctor to look more closely, while a high value is usually not a worry on its own. Any decision about further testing, medicine, or pregnancy planning is best made with a doctor according to your age, cycle pattern, and personal goals.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.