AMH is used as a marker to gage a woman’s remaining egg supply. A woman’s AMH level is categorized by an expected range for her age, so if a woman has a lower than expected AMH for her age she will be said to have “diminished ovarian reserve.” I will note that while I have seen someone’s AMH increase (though theoretically impossible), it will rarely bring them to a different range than originally.
The purpose of measuring AMH for fertility is multiple: it gives an estimate of remaining reserve, and is more powerful in combination with antral follicle count (or AFC, found via ultrasound). The AFC is the number of follicles (eggs) that an ovary is starting to mature in any given month, of which only 1 will become dominant (and be ovulated) in a non-medicated cycle. Together, the AMH tells us about ovarian reserve and AFC tells us what the body is able to recruit each month. If both of these numbers are low, then we would truly put them in the diminished ovarian reserve category. If AMH is low but the AFC is still approximately 15+, we would consider that to be good fertility potential.
The biggest point we tell women about their AMH is that it is most clinically validated as a tool to guide medication dosing for an egg retrieval (in an IVF cycle).
It is NOT meant to give a prognosis of fertility in a patient using timed intercourse or IUI.
So if you have been told you have diminished ovarian reserve and that you may not get pregnant without medical assistance based on AMH alone, it’s an incorrect statement. AMH does not determine your ability to conceive as long as you are able to recruit and mature one fertilizable follicle each month. During fertility treatment, sometimes medication is used to try to get 1-3 fertilizable follicles each month - it increases the odds that one will fertilize, implant, and become a successful pregnancy. AMH still does not determine your body’s ability to do that.