My heart goes out to you and your lost angel. My mother is wheat intolerant too, coeliac seems to skip a generation. She has told me before very lightly about 2 miscarriages she had, but has never gone in to it. As far as I know my Nanna didn't have any. My mother did want a family of six, but stopped at two because of the miscarriages. I hope this confirms your myth a little bit more. Celiac.com has a wealth of information on the matter. I found it very useful when I was first diagnosed.
BTTW - no good baby news soon for me!! I am all done after my three angels, which I use that term very loosely with them, and they keep me very busy so we are considering our options to opt out of baby making...