Hello there! I am new to this forum but quickly spotted your post.
I have had the EXACT SAME experience as yourself . I have two children. I got on the Mirena IUD right after my second child. I just recently got off the Mirena a few months ago. I too became pregnant a few months after and just learned that I had a miscarriage at about 6 weeks as well. I have never had a miscarriage before and never had any issues conceiving. I ALSO DID HAVE A LARGE cyst on one side and also had surgery to remove it as well.
I too wonder the same thing, my doctor did a d&c and also took a biopsy of my uterus to see if there are any issues with it( possibly due to IUD????) I go in two more weeks to get results...I suppose if there is an issue the doc will let me know why, but I am convinced it may be due to iud .. But don't know...
