How does AMH testing help assess fertility at an older age?
AMH can be helpful at an older age because it gives an idea of ovarian reserve, meaning roughly how many eggs may remain. But from my understanding, it doesn't tell you anything about egg quality, which is where age becomes a much bigger factor. I've seen women with relatively good AMH in their late 30s still face challenges, while others with lower AMH did better than expected. That's why I tend to look at AMH as just one piece of the puzzle rather than the whole picture.
AMH test gives the doctor an idea of the ovarian reserve, to estimate how many eggs are remaining, It does not tell that you are going to get pregnant or not. However it helps to find fertility treatment options specially for a person with more age.
From what I've learnt reading up on fertility, AMH is more of a marker of ovarian reserve than fertility itself. It gives an idea of how many eggs are left, but it can't tell you whether you'll conceive naturally or how good the egg quality is. As we get older, egg quality naturally declines, so doctors usually look at AMH along with age, AFC, hormone levels and the overall clinical picture instead of relying on a single number. I remember being surprised when I realised how much context matters because it's easy to get fixated on just one test result.