I'm sorry to come into a group as a newbie like this, but I had to share my story because it might have relevance for some of you who are also facing low reserve angst. I hate to be one of those 'miracles happen!' posters, but...
Five years ago at 27, I was TTC. My cycles were irregular when I came off the pill, and 9 months later I was diagnosed with low reserve. I'm in Australia so our unit of AMH measurement is a bit different but my day 3 FSH was 19, LH 9 (you can see where this is going), and AMH was 12 (1.68 in US measurements), which was classified as low reserve.
A few months later (and no luck TTC), my relationship broke up (thanks in part to fertility stress) and I stopped thinking about it all for a period of time. I then met someone else, and decided last year at 32 years of age that I needed to reinvestigate all of this again. I went off the pill and had my levels tested- the ratio of FSH to LH was still 2:1 which isn't great, even though my day 3 FSH was lower (8 this time, but they do say your highest is most predictive)... my AMH, however, was 6. (0.84 in US). I knew it'd have decreased over those years, but it was still difficult to process. I was only having periods once every three months, and it all felt a bit hopeless, really. I began a process of grieving my fertility.
I had been exercising regularly and maintained a BMI of around 18 for most of my adult life. Coincidentally, after those results, I went on a 3 month trip which prevented me training regularly, and gained weight to a BMI of 19/20... On my return home I started to cycle regularly for 3 months, and on the 4th month fell pregnant, much to my surprise.
Unfortunately I miscarried at 7 weeks, but the fact I actually experienced a pregnancy was amazing to me. That was two months ago, and I've just had my first cycle post miscarriage and had all of my levels retested at day 3. I'm utterly shocked. My FSH and LH ratio is still out (6 and 3 respectively)... My AMH, however, just came back in the normal range, at 25 (3.5 in US). As in, it is now double what it was 5 years ago, and 4 times what it was last year- despite being done at the same lab last year. To say I'm shocked would be a huge understatement. I questioned my health providers (GP and my gyn) about this, who both indicated that while there may not be a lot of peer reviewed papers that suggest the AMH test is unreliable, the reality is that individual circumstances do play a role, and there are always outliers. My gyn also suggested there's not a lot of evidence on the impact of malnurishment/over exercise and AMH, but that there's likely to be some relationship there that we're not fully across yet.
So... I just wanted to post this out there for those of you going through a similar journey. If you've had an eating disordered past, as I had, and are struggling with low reserve indicators, it's worth trying to raise your body weight and seeing what happens. My results didn't suggest hypothalmic suppression, but ultimately that seems to be somehow related. This doesn't mean my low reserve is 'cured' and I'm not trying to promote that idea- but please don't give your body to stress when you get poor results with a presumption it's definite.
My journey isn't over yet and we'll be trying again, but I just wanted to share this after facing so much angst over my previous results.