We'd been trying for around 3 months when I started to use OPK's. First month, no O, every month after I O'ed. Then I got a blood test done and progesterone was normal and I had O'ed on that month. Just before we started trying I went to my doctor and she gave me a checkup and did bloods and things to make sure everything with me was ok and to get the go ahead to safely and healthily TTC.
6 months on and still nothing, so we got DH's sperm tested and we found the problem there.
So if OPK's are telling you that you do O most months, then request a blood test to see if you have O'ed and what your progesterone level was at. They normally request the test to be done on CD 21. You could also ask for other things to be checked that might affect you not falling preg. But as you probably know, they do say it takes most couples 6-12 months to fall preg, but we all know that even after a month or 2 without a BFP it gets really hard!
If all that is ok, then I would suggest you get OH tested as it is much less invasive than female testing.
Please let us know how you get on, i'll be thinking of you and I have my fingers crossed that everything is normal and your BFP is just around the corner
