We fell our very first month trying, but it was unfortunately a blighted ovum. When I had some tests done afterwards, I discovered that I had an AMH of only 6. (I'm 35). I was absolutely devastated, but my naturopath told me that * the results can be affected by whether you're deficient in Vit D (which I was) * it was a new test and there wasn't really a standard sample storage or preparation protocol, so you could get different results from different labs or different collection centres * it's a measure of how many eggs you have left, not what quality they are, and * it has nothing to do with whether you're ovulating each month or not.
After doing some research, I've reached the conclusion that it's a useful number if you're doing IVF, because it tells them how much to stimulate you and how many eggs they're likely to collect. But if you're TTC naturally, then it's not really that meaningful. It tells you how long you've got left to TTC, not what your chance of success is each month. The important thing to check is that you're ovulating each cycle.
After the blighted ovum, I started seeing a naturopath and an acupuncturist to get myself in the best shape I could. And we fell on our 5th month after the D&C. So I can honestly say - lower AMH is not the end of the world. I kind of wish I hadn't had it tested, because it caused a lot of unnecessary angst!