Hi boy mom. I also had the mirena in for a little over a year (about 15 months) and it definitely screwed with my cycles. I know they say your fertility should return immediately, but that is not the case with all women. I am now on cycle 6 of ttc with one early m/c at cycle 3. I was ovulating way later than I usually did and having a short and varied luteal faze for my first few cycles. Cycle 5 was my most regular cycle, so I'm hoping my body is finally back to normal. I don't know if it would have happened sooner if it wasn't for the m/c, which quite frankly, I also blame on the mirena. I also use the clear blue advanced opk, but use cheapies to back it up. One thing about the clear blue advanced is that once you get a peak reading, you are not to test anymore at all that cycle. If you wait for it to clear after 48 hours and start testing again, it assumes you are on a new cycle and the results aren't accurate. Go to their web page and read about it. If you want to keep testing, you have to use another form of OPK. I for one hate that you can't keep testing with it and won't be using it again after this cycle. I still have a couple sticks left, so I'll use those and then go back to ic's and the regular clear blue.