I got pregnant AFTER I lost weight, but I have no way of knowing if it was BECAUSE I lost weight... We'd been trying for a while (not nearly as long as you though), and I started out morbidly obese... I got pregnant within a month or two of reaching "overweight" status (as opposed to "obese" or "morbidly obese").
I do think that my approaching a healthy weight allowed my hormones to even out (I have PCOS), but like I said, I don't know if it really CAUSED me to get pregnant.
I hope that helps, and I wish you luck in your journey