TTC and too thin??

I have always been thin and have a very hard time putting on any weight. I'm 5'10" and weigh 117 lbs. So my bmi is like 17%. I have had 2 miscarriages in the past 9 months. Could my weight be a factor?? I'm perfectly healthy otherwise. Eat right, don't drink, don't smoke, workout. All that good stuff. I have an almost 3 year old daughter and I was about the same weight when I became pregnant with her. So I'm just curious if it could be causing problems for me TTC. Opinions please! Thanks in advance.