You have likely heard of AMH — and maybe have even had your levels tested. But what is it exactly, and what does it have to do with your fertility? In this article, Dr. Sarah Zadek, ND, breaks it down.
AMH Origin Story
To understand AMH, it helps to understand where it started and when it comes into play.
Every cycle — in your ovaries — a small group of follicles (each containing a premature egg) is selected to grow. Anti-Mullerian hormone (AMH) gets made by those small follicles. It then triggers them to begin making some estrogen so they can start growing.
During this process, one follicle will produce more estrogen than the others — we call this one the “dominant follicle.” Once this happens, AMH tells the rest of the smaller follicles to stop growing — a chosen one has already been selected so the others can stop trying.
AMH and Fertility
AMH testing can be used as a marker of your ovarian reserve (number of eggs) since it gives us a clue about the number of follicles recruited during your cycle. AMH decreases as we age, which makes sense. Your egg reserves decline with age, so AMH should decline as well. However, this isn’t the case for those with PCOS.
AMH and PCOS
When it comes to PCOS, having high levels of insulin and/or androgens (like testosterone and androstenedione) means that way more follicles are recruited each cycle. Higher follicle activation means higher AMH. So, in many cases of PCOS, we often see abnormally elevated AMH levels.
High Levels of AMH
Excessive AMH levels can cause problems. It regulates follicle growth and stops follicles from growing too large; therefore, in those with PCOS, it’s possible to have ovaries full of premature follicles (“polycystic ovaries” or PCO) that will never grow properly or reach maturity.
Testing your AMH
By testing for AMH, we can’t know for certain what your egg reserve is like, but it’s a really good screening test. If you’re flagged as having high AMH, it could prompt further testing to find out if you have PCOS and if you’re ovulating.
Meanwhile, having low AMH can flag smaller follicle cohorts each cycle, and can prompt those women to start trying to conceive sooner, or speed up fertility treatments (including egg freezing).
Keep in mind that AMH only gives us an estimate of the number of follicles being recruited to grow each cycle. It can’t tell us anything about egg quality or ovulation. You can still get pregnant and have a healthy live birth even with a low for-age AMH. Similarly, you can have PCOS and high AMH levels, and still be able to get pregnant, just with a few extra challenges.